The American League Is Rolling Again
Let’s see, what are some of the current baseball headlines? With the Mets, Yoenis Cespedes is performing like an MVP candidate (for crazy people). Johnny Cueto’s season has taken a nasty turn in Kansas City. J.A. Happ has been a wonderful surprise find for the Pirates. Troy Tulowitzki might not play for the Blue Jays for a little while, but even the healthy version was offensively under-performing. Carlos Gomez hasn’t quite looked like himself. Cole Hamels hasn’t quite looked like himself. Maybe these aren’t all the biggest headlines in baseball, but they are at least things that are happening.
And there’s something all those players have in common: they’ve all very recently switched leagues. Some went AL to NL, some went NL to AL, and while the league switches don’t explain everything, you have to think they’re some kind of factor. In that, they can’t be considered irrelevant. Because, once again, the evidence points to the American League being the superior league. This isn’t anything new. Rather, this just continues a trend, a trend that’s lasted for more than a decade.
This is something I like to look at late every summer, and though this season isn’t yet totally complete, it’s most of the way there, and I’m an impatient person. The numbers we have now shouldn’t change very much. I want to take this chance to point to this recent Community post by Rob Mains — Mains did good work, and he pointed to the AL’s continuing superiority. Below, I’d like to show you more data, deeper data, so you can see how the numbers have bounced around.
There is no perfect way to compare the two leagues. As far as I can tell, there are three options:
- make up stats
- analyze the performances of those who’ve switched leagues
- look at the head-to-head matchups
The first option is appealing, but dangerous. The second is interesting, but a little complicated, and limited by sample sizes. The third is the obvious one. Every year, the AL plays the NL a few hundred times, and while it would be analytically preferable if they played a few thousand times, there’s neither time nor demand for that much baseball. So we go with what we’re given, and we assume that a lot of the scheduling imbalances even out.
As I write this, there have been 281 AL-NL games. The last few years, they’ve ended up at 300. Previous to that, they settled at 252. Here’s a plot of American League winning percentage over time, in those interleague games:
The mark this year is .548, up from last year’s .543. The average over the whole span is .526. Overall, the AL has controlled interleague play, and it hasn’t lost at least half the time since 2003. This year has allowed the AL to further distance itself from the relatively mediocre 2013. But, say, you might be thinking that this is based on a somewhat small sample of games. Not that there’s much we can do about that, but what if we tried to erase some of the noise by looking at Pythagorean winning percentage? After all, run differential is important. Wins can be fluky.
Stronger. This year, the AL comes out at .569, compared to last year’s .540. The overall average is .532. This year’s Pythagorean record is the AL’s best since 2008, when the leagues were in a particularly lopsided cycle. Now I have just one more graph. The first was of raw wins. The second tried to strip away some noise. This one tries to strip away more. This eliminates sequencing, functioning a little like BaseRuns. Interleague OPS differential, from the AL’s perspective:
At +.056, the AL is again doing its best since 2008. The overall average is +.026, and only three times has the AL come up negative, the last time being 2002, when it was at -.002. This year suggests the AL might be getting back to its relative heyday, after some lower years. Or, it’s just a blip. These things are cyclical, but I can’t predict the cycle from here. I don’t see any reason to think the AL will give up this advantage soon.
Whenever this comes up, it’s always controversial. Sometimes NL fans feel disrespected, and, though there’s no fixing that, this is just what the numbers say. I assure you, I’d be delighted to write a similar post about how the NL has gotten stronger than the AL, were that to happen. I’m just writing what I see. Additionally, NL fans sometimes talk about how interleague play puts them at a disadvantage, because the AL has regular designated hitters. It’s not a clear-cut case, but even if it is somewhat true, the fact of the matter is that this year the AL is doing better against the NL than it has on average. So even if the AL gets a little interleague edge, then if you take the whole window as representing an even balance, this year the leagues are uneven. This year, I don’t know how you could demonstrate that the AL isn’t the better of the leagues.
Some points of possible interest: this year, the average AL team had an opening-day payroll a little under $2 million higher than the average NL team. Last year, the average NL team was higher by a bit more than $2 million. But in truth, this doesn’t mean anything if you don’t take service time into account.
And then, pulling from Man Games Lost, this year the average NL team has lost 776 games to injury. The average AL team has lost 676, exactly 100 fewer. But right now we don’t have a good measure of how important those missing games have been. It’s a partial explanation for the discrepancy in success. I’m skeptical it’s a big one.
Cherry-picking, five teams in the National League stand out, in a good way. I’m referring to the Cardinals, Dodgers, Mets, Cubs, and Pirates. Those teams have won 53% of their interleague contests, which is good. But then, they’ve won 60% of their intraleague contests, which is much better. So they’ve run into some obstacles. As expected, the AL has beaten up on the NL’s dregs. This year’s dregs are really dreg-y. Should be better next year, but, I don’t really know.
In closing, if you want a neat little way to think about this, we can make use of the Log5 equation. Let’s take just this year’s AL interleague winning percentage. If you think that reflects real ability, then the AL would be a “true talent” .525 league, and the NL would be .475. So the average interleague game would be like an 85-win team playing a 77-win team. Let’s now say, instead, you believe more in the Pythagorean record. Then it’s more like an 87-win team playing a 75-win team. The difference between the leagues has been big. It’s existed for a while, now, but this year it’s grown. I don’t know if it’ll stay like that, or if it’ll go back down. I don’t know when the NL will appear superior. I’m sure it’ll happen. It’s just not happening at the moment.
Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.
Now I’m wondering if the difference is just going to get bigger next year. The NL has a bunch of teams that look to be in full rebuild mode (Phillies, Braves, Reds, Brewers, and Rockies), while pretty much every AL team could talk itself into upgrading a little bit and hoping to contend, given the parity shown this season.
Yeah, I was thinking along these lines as well. This year’s AL is clustered much closer as a whole and the NL is more spread out. One standard deviation of win percentage in the AL is .042, while one standard deviation of win percentage in the NL is nearly double: .078.
So while the ‘good’ five teams in the NL may play well in interleague play, their success is obviously offset by the terrible play of the other ten teams. And this also explains why those five teams play better against the rest of the NL than against the AL: those crappy ten NL teams are really lousy. Indeed, the median win-percentage NL team is the Diamondbacks. Where would their record rank in the AL? Tied for 12th. Meanwhile, the NL has two teams better than anyone in the AL, and four teams that would all be better than the second best team in the AL.
Next year, yeah, things will likely repeat themselves, since most of the AL is competing for mediocrity, by the looks of things, while the NL is more winner takes all.
Yes, to put it in Sullivanian terms, in the 2016 NL the dregs seems destined to get even more dreg-y. But maybe some of the teams in the middle will get enough better to counteract that. At least partially.
As crazy as it sounds, the entire disparity in overall quality of the leagues comes down seemingly almost entirely to the DH. AL pitchers have to actually pitch to 9 professional hitters, while NL pitchers only get 8+a guy who (in most cases) hasn’t even attempted hit for most of his adult life.
This effect is twofold: the “free out” that pitchers usually (exception: Bumgarner) supply their opponent is huge, it kills rallies and keeps a lot of pitchers out of trouble that they’d find themselves in if they were in the AL and facing say, Jackie Bradley in 2015. When a guy like Cueto is used to that free out every 8 hitters and instead is faced with a guy with a .650+ OPS instead of a .250 one, he can and will get exposed. Meanwhile lifetime AL guys who go to the NL end up going “Wait, I get a free out? The rules!” and a lot of the time start dominating or vastly surpassing their ceilings, like Greinke and Arrieta. A great pitcher is going to be great in both leagues, but many lifetime NL guys often flounder in the AL due to this. This also is a trickle down effect for hitters, being as NL pitchers are actually allowed to let their guard down, they become used to that being an option, and often will drop their focus to throw BP to the pitcher, whereas in the AL they have to be 100% perfect at all times to not get obliterated. Lifetime AL hitters will often find themselves having career years in the NL too, as NL pitchers focus isn’t as steely as AL pitchers, and they will also find themselves catching more bad pitches that wouldn’t even be in a great AL SPs repertoire.
That being said this disparity doesn’t mean anything in a 7 game sample like a World Series, but over many games its becomes glaring. The AL is simply a stronger league due to it providing 9 hitters vs. 8.
I feel like your observation could be tested, such as looking to see if the AL has more big innings or the effect size of where in a lineup an inning starts is larger in the NL (under the notion that starting with the 7 spot in the NL is less likely to lead to a multi-run inning than if it was the AL.
I feel compelled to point out that Bumgarner has a higher strikeout rate than any qualified hitter and a walk rate that would be in the bottom ten of qualified hitters. I think you could still call him a relatively easy out.
No. If the DH had that big an impact, you would just find that the NL as a league scored fewer runs in their intraleague games. If you don’t find that, either the DH has a smaller impact than you think, or NL hitters are better than AL hitter, or NL pitchers are worse than AL pitchers. Anyway, in interleague play, you would find AL lineups decline to the NL scoring level and NL lineups inflate in AL parks, but either way, you would expect the interleague record to be .500 if the leagues were equal strength.
Puts a little damper on the idea that the 2015 NL Wildcard game is specially epic. The AL Wildcard teams will have worse records but might not be that much worse overall.
BAH
I just think the pitchers are way tougher in the AL. I think the starters throw way harder, and also due to the rules, they stay in the game much longer. NL players start facing scrub AAAA players in the 6th inning of most games, on both sides of the ball.
You could look up these points on this site, and you would see that each league’s starters have an average fastball of 91.7 MPH, and AL starters throw 5.87 IP/GS and NL starters throw 5.80 IP/GS. The inning disparity only adds up to 11 more bullpen innings in a full season for one team, so I’m guessing that has very little to do with the AL’s greater success.
The time in game explanation doesn’t make much sense, since it would mean NL starters would pitch longer in AL parks and AL starters shorter in NL parks, and there would be no advantage for either league. However, AL starters may in fact just be better than NL starters.
I’m still shocked at how fragile Tulo is?? I had a fat woman run into me at Walmart much harder than that collision and I’m fine.
please
fully conditioned pro athletes and a fat woman at Walmart?
do you also buy groceries at Walmart?
I barely winged you, liar.
You almost knocked me into next week!! My shoulders are fine though.
You do have fine shoulders, baby. Meet me in the Denny’s parking lot and we’ll work it all out.
If you review your basic physics you could not have collided harder with the fat woman:
1) I run a lot faster than the fat woman
2) I weight 205 lbs, making me nearly as heavy as that fat woman
3) My chiseled jaw does not have the same collision safety rating as the fat woman
Therefore you could not have collided harder with the fat woman. QED.
Jeff, you should find some data that shows the disparity in teams records in AL parks vs NL parks. I have a feeling that with the DH, the AL is dominating their home games. The NL team with the best interleague is the Pirates at 13-7. Yes, they played mostly the AL Central but they also had the depth to place a good hitter at DH. The NL is at a disadvantage because they don’t have that extra player to hit the way an AL DH can. Often-times, a backup will play with a starter playing DH so the NL team is essentially using a guy not good enough to start in the first place to replace the pitcher. Whereas, in the NL parks, the AL just has an extra bench bat and it’s evened out pretty much.
The AL is 82-56 at home and 68-66 on the road.
Teams are supposed to be better at home, and there is a much bigger advantage for an NL team in an NL park than an AL team in an AL park. AL teams can at times be forced to remove their best bat from the lineup; NL guys are merely adding their best bench bat to the lineup in an AL park.
The fact that the AL is winning on the road says a lot about the disparity between the two leagues.
Or the uneven “Rivalry” schedules.
The rivalry schedules usually involve playing in both parks in a season, and in any case, any effect of that would be nonexistent over the large sample of AL success we have.
Is this the same year to year, though, or is it just this year that the AL is winning more in NL parks? Even then, the record is barely above .500; they aren’t exactly dominating, although a winning record is a winning record.
I’d also like to look at how many of the interleague games are one-run games, which (unless I’m mistaken) tend to go either way. So maybe it’s luck? I truly have no idea; I’m just tossing out (probably bad) ideas.
The AL is 82-56 at home and — all right, I see I’ve been saved the trouble
Yes.. to spell it out a little more clearly, the “normal” home team win % is typically cited in MLB as 54-55% or a 8-10p spread. The spread in inter-league this year (based on the above WL records) has been 8.7p (0.594 versus 0.507.)
That would suggest that the difference in parks / rules / DH is not meaningful and the level of talent is meaningful.
The four worst teams in MLB are NL teams. It’s possible the six worst teams are in the NL. There have been years when the NL has been on par with the AL, but it’s been rare in the last 30 years (and really more) when the NL was better. It’s been all AL. The history of baseball shows cycles when for long stretches one league dominates. The AL is one of them now. The question is why. The Yankees rise in the 1990s might have been a recent contributor. It forced teams to become more innovative. It is probably no surprise that NL teams like the Cubs and Dodgers restocked their front offices with AL talent. History says this will eventually even out, and indeed the NL may become the dominate league again for another stretch, but that is not the case today.
As a NL fan, the trends pointed out in this article would bother me if not for the fact that the NL has dominated the AL in the World Series the last 10 years (6 NL wins to 4 AL wins).
My theory is that AL teams tend to dominate in interleague because they generally have deeper and better rosters of position players. But the NL teams have better elite starters, and in the postseason with all the off days this superiority in starting pitching can best be leveraged.
Why are AL teams better and deeper in position players? I believe a major reason is the AL, fueled in large part by big spending especially in the AL East, tends to give out the biggest free agent contracts which has resulted in a general talent drain from the NL to the AL. Think of Fielder, Pujols, McCann – all jumping to the AL. Are there any similarly high-talent AL hitters who have jumped to the other league? With the DH, AL teams can also afford to maintain an extra position player on their rosters so they have more hitters to choose from every time they make out a lineup.
As long as the AL gives out the biggest FA contracts, this talent drain will likely continue. But as long as the NL equals or betters the AL in WS titles, it won’t bother me as a fan. I think WS titles are the ultimate goal and achievement, so that’s what’s most important over a long season. Not some interleague game.
>>if not for the fact that the NL has dominated the AL in the World Series >>the last 10 years (6 NL wins to 4 AL wins).
Does not compute!
Is that sarcasm? Because what I wrote is true — The NL has dominated the AL in the WS the last 10 years.
The AL is a hitting league and the NL is a pitching league. This is of course overly simplistic, but because the AL adopted the DH, the two leagues diverged this way. I think this has allowed NL teams to more easily develop and nurture elite pitching which can be leveraged more easily in the postseason. Hence you see this dominance in the WS.
The NL is 28-25 in the World Series the last 10 years, hardly dominant. Last year, Bumgarner was the only Giants starter who could get anyone out. In ’12, Zito and Vogelsong each had great starts, and I really hope you don’t think they’re elite. In ’11, the Rangers had better starting pitching, but their bullpen and defense gave the series away.
I’m not sure I would call one extra series win “dominance.” The AL has actually won more WS games over the past ten years, 49-44 by my count.
The past ten years is exactly one Ned Yost different from being 5-5 in titles.
LeeTro — Last year, the Giants starters outpitched the KC starters. In 2012, the Giants starters outpitched the Tigers starters. And in 2011, the Cardinals starters outpitched the Rangers starters (not by much, but they did). It is not true the Rangers starters pitched better in the 2011 WS.
And if you’re calculating WS dominance by individual games won vs. series wins, you’re crazy. The players or fans don’t really care about individual game wins compared to series wins. It’s the whole series that matters. The NL has the edge the last 10 years, 6 to 4.
We’re querying ‘dominated,’ because a six-to-four lead in WS play is not dominating. This is an NL lead of 28-25 in games, 224-209 in runs. If you want to regard this as definitive, feel free, but I don’t think 53 games amount to a particularly large sample from which you can reach conclusions based on one League’s domination
“And if you’re calculating WS dominance by individual games won vs. series wins, you’re crazy. The players or fans don’t really care about individual game wins compared to series wins. It’s the whole series that matters. The NL has the edge the last 10 years, 6 to 4.”
Has the edge, or dominated?
L. Ron Hoyabembe, I don’t see how it’s possible the AL has won 49 of 93 WS games over a ten year period, considering at absolute maximum there can only be 70 WS games over ten years. The 28-25 actually feels a bit light but I think there is at least one four-game sweep in there (’07 Red Sox) and maybe two (’05 White Sox?) so that could explain just 53 games over ten years.
CSW — I would say “dominated,” but let’s not quibble over semantics. You can use any word you like.
Suffice it to say the NL has won 60% of the WS titles over the last 10 years. That’s a higher percentage than the percentage of interleague games won by the AL the last 10 years. So if you use the word “dominance” for interleague, then I would think one could use that word for the WS too.
Regardless, as a fan I couldn’t care less about interleague compared to WS titles. The latter is far more important to me by a mile. I’m sure the players would say the same thing.
Metsfan, yeah the players would say that. But would you still be singing the NL dominance tune if Salvador Perez hits a two-run walk-off home run last year and the WS score is knotted 5-5. You cherry picked ten years because you go back further and the AL looks better. The NL is 6-5 last 11, 7-5 last 12, 7-6 last 13, 8-6 last 14, 8-7 last 15, 8-8 last 16, 8-9 last 17, 9-9 last 18, 9-10 last 19 and split even 10-10 since the strike. Go shorter and the NL actually looks *dominant* at 6-3 last 9, 5-3 last 8, 5-2 last 7, 4-2 last 6, 4-1 last 5, 3-1 last 4, 2-1 last 3, 1-1 last 2, and 1-0 on account of a win last year.
Anthony — not just the player, but fans too. Most fans couldn’t give a crap about interleague. All they care about is the postseason/WS for their team.
And I posted the reason below why I chose ten years. Let me repeat:
“I used 10 years because (1) it’s a nice round number (2) anything less would suffer more from it being a small sample size (3) 2005 is roughly the time Jeff Sullivan is covering in his article and the time the AL started showing a bigger dominance in interleague play. So it’s the period of time under the microscrope.
And I exclude the Yankee years because during that time (1) only they were spending huge amounts on payroll and garnering most of the lucrative free agent contracts; there is more parity today and (2) no PEDs testing back then.”
I should add that 2005 was also the first year where MLB PEDs testing started getting serious. And, yes, I do believe PEDs-fueled players have had a big impact on the WS prior to then.
Metsfan, again, that’s nice, but it doesn’t really matter in the grand scheme of things. I don’t think many Mets fans really care that the NL won considering the Mets didn’t win. One team wins the actual World Series, not 15 teams sharing a league. As a Mets fan just like you, I really don’t care that the National League has won six of the last ten World Series using specific endpoints to prove your point. It simply doesn’t matter to me. 28-25 in actual games matters a little more to me, but I would waaaaaaay rather see the result of a few hundred interleague games in any given year then a seven-game series. The postseason is awesome and it’s what teams and fans love to play for, but it’s very rarely demonstrative of anything of actual statistical significance. Interleague records are better, though I don’t even love those for the obvious caveats of league differences.
Anthony, let me ask you — How many fans do you think know which league has won more inteleague games over the last 10 years or so? How many fans do you think know the NL won more WS titles over the last 10 years or so? I would bet the latter is much more than the former.
Second, how many fans do you think would say they care more about interleague wins vs. those who say which league wins the WS is more important? Again, I bet the latter would be more. Much more.
Interleague is interesting and I like it. But which league wins more in interleague is of little importance to me. OTOH, I as a Mets fan am a NL fan too. I almost always (though not always) root for the NL team in a WS no matter what teams are involved.
So if you want to cherish interleague games more, so be it. We will agree to disagree which is more important from a fan perspective.
Anthony, you’re right, I screwed up the math. The AL has won 25 games in the past ten years. I tallied up their wins in seasons they lost the world series (9 total) then erroneously added that to 40 instead of 16 in an attempt to shortcut. I think I got 40 from 4 to win the series times 10 years but obviously the AL has not won the each of the past 10 years.
Socks slept in 07 and 04.
At it, you’re only going back 10 years my bad
Looking at overall won-loss record in World Series games is misleading. If the two teams are not evenly matched, then the series only goes four games. If they are, the series goes seven games. So, the series in which the teams both play closer to .500 ball get weighted more when tallying up the full number. The number of games played depends on how unbalanced the matchup is (so, probably, the AL should actually look a little better over the last ten years).
Not that this matters, because a team winning four games to start doesn’t mean they’d continue to dominate for three more, since World Series teams are probably close to evenly matched anyway.
The one thing we can get from analyzing World Series results is that it doesn’t seem to matter which league is stronger (here, “stronger” means “if my team played in this league, it would lose more games than if it played in the other league”), or at least we don’t have any strong reason to believe it matters, at least for the sake of which league wins the World Series.
Is this guy really trying to discredit thousands of games of interleague play with 10 best of 7 series?
No. They are almost apples and oranges.
But Metsfan, it sounds like you’re arguing that NL isn’t really inferior because the (likely) best team from the NL has beaten the (likely) best team from the AL 6 out of the last ten years. That doesn’t mean the entire NL is better than the whole of the AL. The thousands of interleague games played represent contests between all of the teams in MLB, not just the 2 best from each league. It’s been pointed out several times already that the NL has a few of the very best teams in baseball this year, but is top heavy. The AL, meanwhile, seems to have more quality from top to bottom, and thus has more parity. So, maybe an NL team wins the world series this year. Maybe an NL team is the best in baseball this year. It doesn’t change the fact that more AL teams won more games against NL teams this year, which really seems to prove that the average AL team is better than the average NL team.
hmk — Please quote me where I am saying what you think I am saying. I suggest you read my posts carefully again because my position is highly nuanced and I think you have misunderstood it.
I don’t know that your theory of elite starters really holds up. elite starting pitchers wasn’t *really* a reliable key for either World Series finalists last year, as the Royals hit fielded and ran all postseason and Bumgarner’s postseason was possibly a generational performance, but it isn’t really the mold of the team anyway. The Tigers failed with all their super rotations to really even make a showing in the World Series, the Dodgers haven’t done anything in the postseason yet with their one-two KO, etc. etc. There’s no key to the postseason, and postseason results aren’t an ultimate gauge of NL/AL power dynamics anyway
Bumgarner certainly fits the mold of elite pitching, and KC had no equivalent last year, did they? Look at the Giants and Cards WS wins the last few years. Aren’t they all built on superior starting pitching to their AL opponent’s?
As for the Tigers, their elite pitching was never deep enough to get them the ultimate prize — especially when you consider mediocre bullpens Dombrowski put together.
I still think elite pitching – depth and quality — is the biggest key to the postseason. It is not the only one, but it’s the biggest. And of course postseason results are not a true gauge of overall league depth or dominance. But if you’re talking about the best teams in each league, I think the NL teams have dominated in recent years in the WS. And ask any player, that’s all they care about. Not some interleague games.
Dominated now equals winning one game 7 in 2011 lol.
If the Rangers win game 7 in 2011, the World Series breakdown is 5-5 in the past 10 years. So pretty much the difference between “dominating” and being dead even according to Metsfan is 1 game 7 victory.
…. or we could use years of head to head data but that doesn’t fit the argument that the NL is somehow better so we’ll ignore that.
I think this post of yours shows you really didn’t comprehend what I was saying really well.
“Dominated” equals winning 6 of 10 WS titles, not one game 7. One game 7 is part and parcel of a WS win.
And yes, the NL is “somehow” better. Not in overall league depth or performance. But their elite teams have better pitching and have dominated the AL over the last 10 WS.
Once again with the word dominated.
You can’t seem to comprehend that the 6 wins in 10 years is tied to winning game 7 in 2011. Oh, and sorry… the Game 7 last year. So if those two 50/50 games split, instead of the NL winning both of them, it’s 5-5 in the past 10 years.
Since 2004, the overall world series record for the AL is 27-28. “Dominating.”
The Tigers pitching wasn’t deep enough to win a championship but the Giants was? Some combination of peak Scherzer Verlander, Sanchez, Price, Fister? Post Hoc Ergo Propter Hoc is the key to the postseason. And to your point about #RINGZ, that’s not really the point of this article. The American League is playing superior baseball.
Daneeka — Daneeka – Look back at that series. The fact is Bumgarner, Vogelsong, Zito and Cain as a group outpitched Verlander, Fister, Sanchez and Scherzer. Game 4 was won in the bullpen, and SF was superior there too. The key to the postseason is whatever fuels the series winner. More often than not over the last 10 years, it has been starting (and overall) pitching. And more often than not the NL has come out on top.
And, yes, I know WS titles was not a central point of the article. But it pertains to and is very relevant to this article. Because from a fan perspective, few really care which league, if any, dominates in interleague. It is really irrelevant for a lot of reasons. In fact, every time an AL team played the Nats, Dodgers, Cubs or Pirates this year, I was rooting for the AL to win.
I was just injecting another viewpoint into the discussion. The AL can continue to “dominate” the NL in interleague for all eternity and it won’t matter to me (and I think to most NL fans) — so long as the NL is equal to or dominant over the AL in the WS.
If you want to say the NL has dominated the AL in the World Series, why in the world would you say they’ve won 6 of the last 10? They’ve won last year, 4 of the last 5 and 5 of the last 7. 4-1 and 5-2 look like significantly more dominant stretches than 6-4. Chicago and Boston won in ’05 and ’07 with four game sweeps that really, really discredit the notion that the NL has dominated for a decade. Going back further (because WHY ten years?), Boston won in ’04, Angels in ’02, Yankees in ’96, ’98, ’99 and ’00, offset by the Braves in ’95, Marlins in ’97 and ’03 and D’Backs in ’01. So in the last 19 seasons, it’s actually 10-9 AL. It’s 10-10 in World Series wins since the strike. Except there’s at least a few AL sweeps and I don’t think the NL has won in less than six in that time. The years the AL loses, it’s very close often (Game 7s in ’01, ’11, ’14, with just a single game 7 loss for the NL in that time (I think ’02 is it)…)
I used 10 years because (1) it’s a nice round number (2) anything less would suffer more from it being a small sample size (3) 2005 is roughly the time Jeff Sullivan is covering in his article and the time the AL started showing a bigger dominance in interleague play. So it’s the period of time under the microscrope.
And I exclude the Yankee years because during that time (1) only they were spending huge amounts on payroll and garnering most of the lucrative free agent contracts; there is more parity today and (2) no PEDs testing back then.
>doesn’t want small sample size
>says 10 best of 7 results are more conclusive than hundreds of interleague games
2001-2014 is a good size, too, and 8-6 by your WPCT measure looks a good bit worse, falling below, I think, the winning percentage in Jeff’s post. I get your point, that they’ve won 60% of the titles, and 60% is a large percentage, but I just flat out disagree that it’s a meaningful sample to draw a legitimate conclusion from. It’s nice, but I would much rather look at actual performance in that time than series wins. It’d be like saying the Mets beat the Nationals 3-2 in their series this season, which I believe they have, and they’ve dominated them on that basis, which is nice to know, but I’d much rather see that they’ve beaten them 10-6 in actual games played. It’s just more instructive, for me. It’s cool that the NL has six WS wins, but honestly, to me, it’s absolutely meaningless when it comes to actual analysis of the A.L. vs. N.L. It only really means there’s a somewhat okay chance that the NL has housed the absolute best team in six of the last ten years, not that they’ve been the better league.
The Dodgers spend more money, in comparison to the rest of baseball, than the Yankees ever did. So….
> It only really means there’s a somewhat okay chance that the NL has housed the absolute best team in six of the last ten years
No, the World Series winner simply tells you who the quickest to four wins was in a 7 game series.
It doesn’t give you a somewhat/okay chance of telling you the best team in baseball was in the NL.
The Cardinals won 83 games and won a World Series. Pretty sure they weren’t the best team.
The 116 win Mariners team didn’t win a title; pretty sure they were the best team.
Giants weren’t the best team in baseball… etc etc.
Didn’t even see this at first, but, yeah, whether you’re looking at 53 games over 10 years, 49 games over 9, 45 over 8, 41 over 7, or so on, you’re still looking at an incredibly small sample.
Rational fan — And when did the Dodgers start spending this boatload of money? We’re talking 10 years here, not 2.
Metsfan, we’re going on year 4 of the Dodgers spending a boatload of money. The Giants – who own three of your sacred six WS titles – also spend a fair share of money, as did the Mets back in ’06-’08, when they came up empty, the Phillies during their recent stretch of dominance, and the Red Sox during their WS run last decade.
Anthony — actually it’s 3 years for the Dodgers. In 2012 their opening day payroll was just $105 million (Cot’s). That’s pretty small.
As for why I didn’t pick a larger sample size, I already explained. Prior to the last 10 years or so there was no PEDs testing and much less parity than there is today. Therefore, the teams fueled by higher payrolls and PEDs might naturally dominate. Also if you look at Jeff Sullivan’s chart, it is about 2005 when the AL started to really dominate in interleague play. Hence I chose the 2005-2014 time period.
“Dominate” = basically .500 over a meaningless sample of 53 games.
OK.
33 comments later, this point is still dumb.
Maybe I’m missing something, but from a GMs prospective, it makes perfect sense that the AL would be superior to the NL.
In the AL, there is a position where defence does not matter. So GMs construct their roster knowing that there is a spot on the roster where defence doesn’t matter. If teams were to do that in the NL, it’d be an awful waste of resources.
Theoretically, negative D guys should never receiver a higher bid from an NL team than an AL team. There’s no reason for guys like Martinez, Ortiz, Morales, Encarnacion, A-Rod, LaRoche, Gattis, Fielder, etc. to end up in the NL.
So when the NL plays in an AL park, their DH is someone whose D they had to value when offering a contract. When an AL team plays in an NL park, they are spending more on a pitch hitter than any NL team would bother.
If the NL and AL had 1000 games instead of 300 games, the valuation would change and you’d prbably expect to see more parity.
There’s no reason for a guy like Edwin Encarnacion to be in the NL? Really.
Man, I’m glad I don’t root for that league then.
LaRoche was in the NL his entire career until this year lol
Gattis was in the NL last year
Fielder was there for years.
What are you even saying?
Rational Fan — I think he’s saying in effect that the NL can’t afford to have someone like A-Rod on their team because he can’t play a position. The AL can therefore pick from the best of the offensive players, regardless of defense. The NL teams can’t really afford to do this. His point about defense if perfectly valid, even if not expressed exactly the right way.
Prince Fielder was a defensive negative who needed to transition to DH in time as he aged. Adam LaRoche was a legitimately fine fielder for awhile. Evan Gattis wasn’t a good fielder at all. They can play in the NL, just like Adam Dunn did, but they’re much better utilized in a DH role in the AL. David Ortiz, Kendrys Morales, Billy Butler, Alex Rodriguez, Edgar Martinez, Victor Martinez, Travis Hafner and Mark Trumbo are all quite fine with the DH rule. Frank Thomas and Jim Thome liked it at the end of their careers, too, and they’re in the Hall/going to the Hall.
Evan Gattis caught 90 games in the NL last year; now he’s not good enough defensively for the league.
No one is arguing Prince Fielder is a good defensive first baseman but he left the NL because the AL offered him more money because they pay players more money in free agency.
According to you, the NL has no room for guys like Prince Fielder and Edwin Encarnacion… meanwhile they are throwing Pedro Alvarez, Ryan Howard, Adam Lind, Wilin Rosario and on and on.
There’s only one DH spot per line-up where the AL can exploit it. Maybe a couple teams will field two DH-types and split the ABs. So obviously there comes a point where the AL teams, or the AL teams with money, have filled up their no-defense spots.
The point is, on a guy like Prince Fielder — if both AL and NL teams decide to pay the exact same dollar amount per win (or run or whatever metric) the AL team is going to value him higher because they don’t have to subtract runs/wins for bad defense. So *theoretically* the elite guys who have awful defense, should go to the AL.
This is baseball, though, and obviously a bunch of things control signings other than just value.
Look at the guys that you mentioned. First none are really elite, and secondly Lind signed in Toronto, Howard is an awful contract, Rosario and Pedro are probably both still in arb.
WAR is going to assign the DH negative penalty to the DH regardless of whether or not he is a great defender. Maybe an AL DH will play 50 games at a position, maybe he’ll just play the 20 interleague games. The point is, in the NL, he’s going to have to play almost all of them.
There’s all sorts of room in the NL for an elite negative defense player. Positive value is positive value. The point is that an elite 0-defense player is worth more to an AL team than he is to an NL team.
As a caveat, the players I listed were just the DHs I could remember. I haven’t actually looked at their numbers.
Kris, the DH in the AL is anything but “elite 0-defense” players.
Scroll over to the DH depth carts: http://www.fangraphs.com/depthcharts.aspx?position=DH
There are a few pretty good sluggers at the top of the list and they are obviously from AL teams. But, look at what happens once you get past #7 on the list, the Yankee. It #8 Brewers, #9 Reds, #10 Dodgers. Many AL teams can’t even match the better NL team’s DHs.
I find this particularly interesting, at #12 is the Cardinals, most of the PAs as a DH are exacted to come from Matt Adams. On the Card’s depth charts, Matt Adams sits behind Moss at 1st and will pick up what ever DH duties are needs in AL parks. He is expect to give a .325 wOBA. That expected wOBA is better than 6 of the team-wide DH wOBA projections from AL clubs.
Most good NL clubs have some sort of 4th OFer, backup 1B that can easily slide into a DH roll during interleague. If you go over to baseball-reference, you can look up how AL DHs did versus NL DHs even. The AL DHs have a OPS+ of 101, while NL DHs have a OPS+ of 86. So yes, NL DHs aren’t as good as AL DHs, but its not a huge lead.
Now in NL parks, AL pitchers are also worse batters. If I got this right, baseball-refence does pitcher specific OPS+, and NL pitchers have 100 OPS+ (almost by definition, since the AL pitchers batting is a relatively small sample), but AL pitchers have a 96 OPS+ when hitting. So these two forces do offset a bit.
Also, all teams are money-limited when it comes to fielding talent, not limited by starting roster spots. So if a team has $100M to spend, its going to spread most of it out on 8 position players, 5 starting pitchers and a few relievers. Backups, the tail end of the bullpen, even 1 or 2 starters, usually don’t make much money. While the AL teams simply spread the bulk of their money out over an additional roster spot. So in theory, if AL and NL payrolls are roughly equal, the NL teams can just concentrate their money in 1 fewer spot, leading to better players in those spots than an AL team.
Now, the money isn’t really the same though. With the Dodgers included, the leagues are only about 1.5M apart, but if we take out the top and the bottom payrolls from each league, the AL has a $5.8M advantage. But that monetary discrepancy isn’t enough to explain the AL’s advantage.
Rational fan – what on earth do Wilin Rosario, Ryan Howard and Adam Lind have to do with the ability to stash bad defenders in the field? Those are not productive decisions, and their teams are among the worst in baseball for reasons like that. Likewise, just because Evan Gattis HAS caught professional pitchers doesn’t mean that he should. That’s an incredible false equivalency.
Walter, as a Cardinals fan, I highly doubt you’ll see Moss at 1B and Adams at DH if they make it to the World Series. With the roster crunch they face, they’re more likely to play Holliday at DH with an outfield of Piscotty, Grichuk, and Heyward, and a 1B platoon of Reynolds and Adams/Moss with the odd man out not even making the postseason roster (assuming they want either Jay or Pham as a 5th outfielder; we’ll see over the last 2 1/2 weeks). They also might just play Piscotty at 1B in the earlier playoff rounds.
The problem is, would this show up in interleague play? The AL has the advantage signing these guys, but when they play in NL parks, the either have to take the hit on defense or not play the guy. So, the advantage is negated. But the AL vs. NL record in NL parks make it look like the AL team is still better, once you adjust for NL home field advantage.
Could this just be a matter of talent distribution? Looking purely at team records, it seems like most of the NL talent is concentrated in a few teams, leaving several pretty bad teams. In the AL, you have a more even distribution of talent (or wins, at least). This would create more opportunities for the AL to win games, even if the talent level is about equal, which it probably is.
I think this comment really hits on it. The 5 NL playoff teams win 53% of the time versus AL against 60% overall, but they also get to beat up on those NL dregs even more than the AL does in interleague so that makes sense. There is no Atlanta or Philadelphia to play in the interleague schedule.
The reason the AL is dominating this year is because there are no outright horrible teams whereas there are plenty in the NL.
The worst AL team is Oakland at 62-83 (but an almost even run differential). Chicago is at -107 and no one else is below -65. There are 7 teams in the NL around or way below the run differential of the 2nd worst AL team. With the top few teams more or less as strong as the NL, the difference at the bottom creates a huge disparity.
Yeah, if you take out our bad teams we’re the best!
I get your point, but I think you missed theirs. They’re basically just saying if you only look at the top NL teams vs. the bad NL teams, then, yeah, they’re going to win a lot. 60% winning percentage is nice, but it’s all against those bottom ten teams since their winning percentage against each other is by default .500. If you looked at the AL record vs. the ten worst NL records and the top-5 NL teams’ records vs. the ten worst NL records, that’d be more demonstrative, IMO.
I understood their point, but to argue that you’re 5 best teams would be 86 win teams in the AL isn’t really an impressive feat showing the strength of the league.
I’m not arguing that, simply stating that the AL is better overall because they don’t have bottom feeders.
Basically NL top teams are good. Most of the rest are atrocious. AL top teams are good. Most of the rest are mediocre. Mediocre is better than atrocious, therefore AL is better overall.
Yes it is talent distribution, but it is the distribution across the two leagues, not within each league.
This is all DH. And I really doubt it is the actual DH batter, it is that the DH makes the AL game easier. You get to rest players more often, keep your starters in deeper into games when they give up quick runs in early innings, it lets you keep bullpen arms in games longer. AL never has to worry about a bullpen arm coming out due to having to bat. The AL only has to to worry about pitcher/batter matchups.
On the offensive side, you get to give everyone you want regular rest without keeping them out of the game, you use a shorter bench so you replace your weakest batter with a bullpen arm.
In the NL, your bench gets about 20% of the at bats in a given season. All of the bench bats matter, a lot. In most games and most series, every bench bat will recieve multiple at bats. In the AL, this is nowhere near as important. You can hide behind the DH, and rest guys without dipping deep into the bench.
AL is easier to play, so of course they win more games when they play NL teams. They have a huge advantage. Ban the DH entirely, this advantage goes away, the AL has to trade a bullpen arm for another bench player, each bench player has to play more games. Then you will see an even playing field.
I think maybe you shouldn’t have dismissed the 2nd option you listed for comparing the leagues.
Yes, it’s a smaller sample size to compare differences in player performance switching leagues, but it’s not that tiny a sample size.
And the big weakness in using team metrics to compare the leagues, of course, is that the AL teams get the benefit of having to build their team with a full time DH slot in mind. The DH distorts too much to take those team stats at face value.
I would love to see a comprehensive analysis of player performance changes from switching leagues. Anecdotally it seems to be the difference would be overwhelming.
MGL did one of these way back in the day for Hardball Times.
Every year Fangraphs, Hardball Times or some other statistically inclined website posts articles concerning the dominance of the AL over NL in interleague play the last 12 years. Every year comments are made trying to explain this difference as something other than talent.
All of those explanations have been studied before and have been shown to be false.
The AL has a winning record at NL home parks where the DH isn’t even used. This is very significant since the winning percentage for home teams in baseball over the last hundred years is about .530 and the NL can’t manage even .500. We’re talking over 3000 games in the last 12 years.
A year or two ago there was a very good article showing that the AL DH vs. the NL DH was basically completely offset by the fact that NL pitchers were better hitters than AL pitchers. I think the conclusion was that the AL got 6 extra runs over the course of a year. Not per team, total.
And finally as someone stated above, although the NL has won 6 of 10 WS, that’s only one more win (certainly not dominance), and the AL has actually been better statistically in those WS games.
When was the last time an NL team won the WS who also dominated during the regular season? I can’t even think who it was. With a few exceptions, AL winners of the WS tend to be dominant all season.
The only argument that I buy as a contributing factor aside from talent is that the DH allows AL teams to provide better rest for the their players and therefore keep them healthier.
Obviously there is no way that could account for the entire disparity (or even most of it) but I think it could be a legitimate factor.
The DH is more than just the batter, if you just look at the batter youre missing the point. The DH changes the types of players you go after in player development and especially in trades and free agency. The DH fundamentally changes roster construction. The DH changes the usage patterns for players, allowing more off days and rest keeping pkayers more fresh and more able to pkay through injuries. The DH swaps out your last bench spot for a bullpen arm. The DH changes every aspect of the game, and makes it much easier for the AL to play the game. They have across the board advantages.
It isnt just about the actual DH batter, it is about the systemic changes it creates in how the entire organization is run.
So… what you’re saying is that the AL is a better game that allows for better players to play it?
I am saying the AL is an easier game. It is easier to build a team in the AL than the NL.
I’ve never understood why people think the NL is at a disadvantage in interleague games. In an AL stadium, the NL team still gets to play a major league hitter in the DH spot. Even if they’re usually a bench player, that player likely gets a lot more PAs per season than an AL pitcher does. In an NL stadium the AL pitcher has to hit, and he likely didn’t pick up a bat all season until a couple days before for a crash course in bunting.The NL pitcher, while still a terrible hitter, has a lot more (recent) experience at the plate. This gives the NL a bigger home advantage than AL teams get at their own parks. The statistics you’ve presented seem to confirm this.
Again, you cannot look at thos from just the hitter. The DH, the literal person playing DH that day, is not the advantage. The advantage is the ability to construct the team, from amateur draft all the way up to the MLB roster and everything in between, knowing that you will have access to the DH. It changes the way you develop talent. In the NL, when you evaluate “this player might be a dh”, that is code for “this player is literally useless”. In the AL, a dh is still a bad thing, but it at least has some value. It changes the way you approach developing talent, who you look for, how you invest in players. It changes usage patterns for players, which changing the wear and tear they recieve both during a season and overall during their career. It changes the way you approach bullpen amange,ent, starting pitcher management, pitch limits, innings limits. It changes how you think about batting order. It changes how you think about stadium construction.
The DH fundamentally changes the game at every single level, whether subconsciusly or not.
It most certainly IS NOT about the literal person playing DH.
Even if you’re right though, the end result is that AL teams are, on the whole, just better, regardless of rules, and the solution is for an NL team to literally just pretend they’re in the AL.
From amateur draft!?!? I think you’re getting a little carried away.
“In the NL, when you evaluate “this player might be a dh”, that is code for “this player is literally useless”.”
Not really. See if this person is a good hitter, its not that hard to be a passable first baseman or corner outfielder. When was the last time some young slugger came up and went straight into DH-ing? It just doesn’t really happen. Pretty much many reasonably athletic person that plays baseball for long enough to make it to the big leagues can learn to play passable defense at hitting-first positions. For the most part DHs are used for roster flexibility and for aging sluggers. Young players that can’t field doesn’t seem to be a factor hardly at all.
I think you might have a bit of point on the lineup flexibility thing. Prior to this year, the recent A’s teams have done a good job rotating players in and out of the DH spot to rest them while still getting their bat in the line up and/or to exploit platoon advantages. Last year Cespedes had 16 games at DH, Coco 12, Moss 12, Donaldson 9, etc.
But if that’s how you approach the DH, that also means you don’t really have an extra decent hitter to occupy the spot full time. In a sense, you’re a roster made for the NL faking it in the AL. So when you rest a player in the NL, you take him all the way out of the line up, except maybe a late PH, were as in the AL the guy might still get 4 PAs.
So when it comes to rest, what’s the real point and the resulting effect? In the AL, the guy presumably gets less rest but can do it more often since there is less of a penalty on the team. While in the NL it might be done less often, but the guy gets more rest.
Maybe there is something to this and it really does work out to give the AL a bit of an advantage, but it doesn’t seem particularly obvious that it would work out that way to me.
I disagree, it is pretty obvious that the AL has a massive advantage. It is the same pool of players, the same pool of executives, same pool of managers, same pool of scouts. Teams have switched from divisions, all of the players, executives, etc are in constant flux. The only constant is the DH. You would need extremely strong evidence to believe it isn’t the DH, Occam’s Razor applies here. Especially since all of the nonsense people quote for why it can’t be the DH does nothing to actually show it isn’t the DH. Looking at the actual literal guy playing DH isn’t where the benefit comes from.
Go listen to Joe Maddon talk about the difference between the AL and NL. He will tell you how it is.
Andrew, yes its the same pool of human resources, but that doesn’t mean its divided equally at any of those levels. And yes, owners, GMs, coaches, players change, but owners and GMs hardly change quickly. The average year an the current ownership group across MLB bought their team was 1999. For GMs its 2007 and with GMs its often more of a changing of the guard to someone similar in philosophy to the previous person.
“You would need extremely strong evidence to believe it isn’t the DH, Occam’s Razor applies here.”
Um, no. That’s a very poor application of Occam’s Razor. One argument relies on it being the DH, the other relies on it being a differing talent distribution. We know there is some distribution of talent and there is no reason to think it should be equally distributed across 2 groups of 15 teams. The assumption that talent distribution is equal is, by far, the least likely assumption we can make here and the one with the most assumptions. When you make the assumption that its the DH, you are also assuming talent at these levels are equal.
“specially since all of the nonsense people quote for why it can’t be the DH does nothing to actually show it isn’t the DH. Looking at the actual literal guy playing DH isn’t where the benefit comes from.”
What what? You mean like how AL teams still beat up on NL teams in NL parks?
In the end the only thing that matters is that real baseball fans abhor the DH and the AL, MLB’s red headed stepchild.
“Real” baseball “fans” abhor the pathetic charade that is “strategizing” around the non-hitter that is forced to bat because reasons.
See what I did there?
Aww somebody really likes their one dimensional DH that’s not even skilled enough to start a 1B ’cause runz :/
Jeff, is there any way to measure how much of this is the bottom of the NL being horrible?
The 5 worst teams in baseball are in the NL. The Braves and Phillies are just horrible — outscored by nearly 200 runs despite each having a period of pretty solid play. While the bottom 5 teams in the AL were seen as pre-season playoff contenders. Of course the AL dominates, and I do mean “dominates”, inter league play as they get to beat up on the bottom of the NL while arguably all 15 AL teams are competitive.
You get to pretty small sample size when you look at top 6 teams vs. AL or vs. NL.
Totally anecdotal, but I think the top 5-6 AL and NL teams are comparable each year, but the cellar-dweller NL teams seem to be notably worse than the bottom-feeder AL teams.
I’m not interested enough (nor competent enough) to break up the inter-league standings by team’s overall win%, but that could shed some light on this.
Another terrible article by Sullivan. He’s been really pumping these out lately.
Starts the article out with anecdotal evidence of player’s switching leagues and doing better/worse. This evidence is meaningless, but that doesn’t stop Jeff from leading with it.
Here is what we know: The AL has beat the NL in inter league play for a long time now so the AL is probably a stronger league overall based on the fact we have a pretty large (though not as large as you would like) sample.
But instead of giving that one liner, Sullivan needs an article so he mades a long diatribe. Now here is Sullivan’s tactic – he will say he did end up saying the only true way to measure AL superiority was inter league record (actual, pythag, base runs), so therefore the fact that he led by citing a few players who switched leagues performed differently and framing it to have some sort of meaning. This is, of course, nuts. To ascribe Cueto’s struggles or Cespedes’ hot streak to switching leagues is absolutely without any merit and Jeff should no better than to cite this.
*know
That’s the only correction you have to that comment?
Any more you’d like to add? Maybe I shouldn’t have said Jeff write’s terrible articles, so scratch the first couple sentences. Please point out anything that is wrong in the last three paragraphs.
I don’t find any explanation of the discrepancy convincing, except for that the AL simply has better players than the NL.
Regarding the alleged DH advantage argument, one could analyze the AL-NL matchups based on which rules they’re playing by. If the AL has a winning record even in NL parks (which might be unlikely given the usual home-field advantage), that would certainly decrease the weight we should assign to the DH argument (though we’re making the sample size even smaller by doing so).
As I noted above, AL teams are 68-66 in NL parks.
I posed this in the chat thread before seeing this one. Probably a bit more relevant here. The other half of the data is eye-opening, when compared with the first half, in my opinion.
Here are the combined records of the top-5 (by wins) NL teams vs the NL and AL:
vs AL: 51-45; 53% win%
vs NL: 375-250; 60% win%
And for the AL:
vs AL: 343-287; 54% win%
vs NL: 57-34; 63% win%
While the parity in the AL may help explain the disparity this year, it doesn’t explain such continuous cases on both ends.
Here’s my theory: Back when hitting was more dominant in the late 90’s and early 00’s, it was bigger home field advantage for the NL to get one of the opponent’s (usually) best hitters out of their starting lineup. Now that the pitching became more dominant than before, it’s a bigger home field advantage for the AL to face an opponent with at least one bench player in their starting lineup.
While looking over Cespedes’ stats today, I noticed something which strongly undermines the notion put forth in the opening paragraphs that differences in league strength are the cause of fluctuating performances for a few recently traded players.
Before coming to the Mets, Cespedes played in 70 games against the NL during interleague games, and over 290 plate appearances he put up only a .667 OPS. This is a larger sample size than the 197 plate appearances he’s had as a member of the Mets so far. If one were looking just at this larger sample size, the conclusion would actually be that the NL is a tougher league.
Interesting. So I looked at past interleague data for the other players named, and in every instance but one, the stats also contradict the argument that was trying to be made:
–Cueto’s lifetime ERA of 2.68 vs. the AL over 178 IP in interleague is in fact better than his career ERA.
–Tulowitzki’s .924 OPS over 447 plate appearances vs. the AL during interleague is much higher than his career OPS.
–Gomez has a .802 OPS in interleague games which is higher than his overall OPS.
–Happ had an ERA of 4.83 in 2012, the last year he pitched for a NL team before moving over to the AL. That’s a higher ERA than any he produced in any year for Toronto or Seattle.
Some of Gomez’ interleague games include those against the NL when he played for the Twins, but he’s played more than twice as many games for NL teams than the Twins so I just used the total number.
The only player Jeff named who falls cleanly into his narrative is Cole Hamels. His career ERA of 4.74 in 205 IP vs the AL during interleague games is much higher than his overall ERA.
Bottom line — the players named with the exception of Hamels just don’t support the theory that was being put forth.
As for what’s really behind the performance fluctuations? For Gomez, maybe it’s because he’s hurt, on the DL and, according to the Mets, had some health issues prior to his trade to Houston. News reports earlier in the season support that theory. For Tulo, it could simply be a difficult transition to a new team and city. Colorado had been the only team he had known for his entire career. For Cespedes? Maybe he’s finally comfortable in his new country, living in New York City with its lively and large Latino populations. But whatever was the cause of Cespedes’ offensive explosion, I’m sure glad it happened when it did.