When you pull up the position player leaderboards since May 22, you’ll see a pair of likely MVP candidates sitting on top of the list. Shohei Ohtani leads all batters with 3.1 WAR during this period and that’s ignoring the additional 1.3 WAR the two-way star has accumulated on the mound over his last nine starts. Fernando Tatis Jr. sits behind Ohtani with Cedric Mullins rounding out the top trio (perhaps this article should have been about what Mullins has done this year). But nestled behind those three is Willy Adames with 3.1 WAR in 64 games. Why is May 22 the arbitrary time frame placed on this query? That was the day Adames made his debut for the Brewers after being traded to Milwaukee from the Rays.

On May 22, the Brewers were 22-23 and sitting behind the Cubs and Cardinals in the NL Central. Since then, they’ve had the best record in the National League at 42-21 and have built a sizable cushion in the standings ahead of their division rivals. That turnaround is due in no small part to Adames’ fantastic performance over these last two-plus months. He’s hit .295/.379/.553 for the Brewers, good for a 148 wRC+, and has played excellent defense at shortstop. With Christian Yelich still struggling to reproduce his MVP-quality production from 2018 and ‘19, Adames has taken the reins as the leading run producer in the Brewers lineup.

When you compare what Adames has accomplished in Milwaukee with what he did in Tampa Bay, it certainly appears as though the change of scenery has made the difference:

Adames has shown flashes of production like this in the past, but he’s been held back by an aggressive approach that’s led to some untenable strikeout rates. He’s taken his ability to hit for power to new levels with the Brewers, and his strikeout and walk rates have both greatly improved. We’re talking about just 268 plate appearances, but there are enough positive signs in his underlying numbers that we could be witnessing a huge breakout from Adames.

Part of that might be attributable to a literal change in his scenery. Last year, Adames tested out wearing non-prescription glasses while playing at home at Tropicana Field. He was having a really difficult time seeing the ball while playing under the lights of the domed field. “I was good on the road; I just couldn’t hit at the Trop,” Adames told Tyler Kepner of the New York Times in an interview from early July.

“After they changed the lights in ’19, it was tough for me to see the ball there. Everybody thought it was mental, but it wasn’t. I was just guessing all the time there because I couldn’t pick up the ball when I was hitting.”

His issues hitting at Tropicana Field are born out in his home/road splits while playing for the Rays.

What he was able to accomplish on the road while with Tampa looks remarkably similar to what he’s done in Milwaukee. But if he was able to see the ball better on the road, and now while he’s a member of the Brewers, that should show up in some of his underlying plate discipline metrics.

I’ve broken Adames’ career down into three buckets: his home/away splits with the Rays and these last few months with the Brewers. Four of the five metrics above stay astonishingly consistent no matter where Adames is playing. But the one that has some significant differences may be the most important. While batting at Tropicana Field, Adames’ chase rate was a touch above league average; on the road as a Ray and as a Brewer, his chase rate falls well below league average.

That tracks with the way Adames described the effect of the lighting at Tropicana Field in this interview with MLB.com:

“Whenever I was out of the Trop, I feel like I was able to recognize the spin of the ball. You could see if it was a breaking ball, changeup or whatever. At The Trop, I couldn’t pick it up.”

In other interviews, he essentially said his approach while playing in Tampa Bay was just guessing at pitches and hoping to guess correctly. Everything about his approach stayed consistent, except for his ability to recognize pitches and lay off the ones that were traveling out of the strike zone.

These issues also affected the quality of contact he made at home as a Ray. Because he was guessing at which pitches were being thrown to him, when he did make contact with a pitch, he was more prone to mishit it, resulting in poor contact quality.

All of his significant batted ball peripherals were considerably weaker while hitting at Tropicana Field. He wasn’t hitting them as hard and struggled to tap into the power he’s displayed throughout his career.

Back in March, I wrote about how Adames quietly enjoyed a power breakout last year despite some major red flags in his approach. All the gains he made in terms of contact quality last year have taken another step forward this year. His barrel rate, hard hit rate, and average exit velocity are all at career highs — and that’s even including his miserable two months to start the season. All of his batted ball peripherals are even better as a Brewer. Even more encouraging, his batted ball profile isn’t as pull heavy as it was last year. He’s spreading the ball around the field again while still hitting for tons of power. He’s still hitting the ball to left field more often than he was in 2018 and ‘19, but his pull rate has come down more than 10 points from where it was last year.

Based on his struggles in Tampa Bay to start this year, it appears as though the pressure to keep his job on the Rays, particularly with Wander Franco looming, may have affected his performance on the field. That pressure, coupled with the visual issues he’s been dealing with over the last few years, really cratered his production. Now that Adames is in Milwaukee, he’s better recognizing pitches and has adjusted his approach accordingly while continuing to build on the improved contact quality he worked on last year. We’ve seen the best version of Adames over the last two months. The Brewers have to be thrilled they’ve found their long-term solution at shortstop.

There is an old adage in baseball that changing a hitter’s eye level pitch-to-pitch will lead to better outcomes for the pitcher. This makes sense on its face: compared to varying pitch heights and forcing a hitter to alter his bat path, throwing two consecutive pitches at the same height should make it easier for a batter to square up the ball. In a New York Times piece by Tyler Kepner, Mike Mussina discussed the importance of varying locations pitch-to-pitch to mess with the hitter’s eye, offering the example of throwing fastballs down and then countering with a pitch up in the zone. Kepner noted that the hitter’s eye would then be trained on a pitch higher in strike zone, affording the pitcher the opportunity to throw a curveball down to induce a groundball, or net a swing-and-miss. David Price has expressed a similar sentiment: “That’s always a big emphasis [for] me, just making sure I’m hitting spots with that fastball – two-seam, four-seam, both sides of the plate, moving it in, up, down.”

In research on the effect of eye level change on college hitters’ performance against fastballs, Higuchi et al. found that quick eye movement as a pitch traverses towards home plate has negative consequences for the hitter. This research was included in Driveline Baseball’s examination of hitters’ gazes when standing at the plate. On these pages in 2015, Jonah Pemstein looked into whether a pitch thrown at a different height than the one that followed it affected how umpires called the pitch at hand. Permstein surmised that this was indeed the case, with umpires less likely to call a pitch a strike at any height if the previous pitch was thrown at a different vertical location.

As I said up top, this all makes intuitive sense. But does it hold up to further scrutiny? The research I cited by Higuchi et al. only included six collegiate hitters and only considered fastballs. While their work was extremely thorough, its scope didn’t consider the hitter population many of us are most interested in (major league hitters) and only included fastballs at a time when pitches are leaning on breaking balls and offspeed pitches more than ever. Pemstein’s research looked at umpires, not hitters; his conclusions give us some confidence that behavior changes when pitchers vary their pitch location, but doesn’t provide insight into the strategy’s ability to flummox batters. I decided to delve into the data myself and see if there was any merit to this fundamental aspect of pitching strategy.

Using Statcast data from the past three seasons, I constructed various pitch sequence parameters to gauge the efficacy of changing the hitter’s eye level. The first parameter involved pitches that were in the strike zone, as defined by the MLB Gameday zone. Pitches in zones 1, 2, and 3 were coded as “up,” zones 7, 8, and 9 as “down,” and 4, 5, and 6 as “middle.” All other zones were considered off the plate. I focused on pitches in the strike zone because we know hitters are more likely to swing at those pitches and generally have success when they do. The in-zone swinging strike rate over this sample was 12.1%, while 28.1% of these pitches were put into play. Batters had a .349 wOBA on pitches inside this strike zone versus a .304 wOBA outside of it. Any degradation in performance on pitches inside the zone would be a real value-add for pitchers. Read the rest of this entry »

We often hear about how pitchers are overmatching hitters these days, and with good reason. In the last 10 years, teams have discovered how to develop velocity at scale. After generations of going by feel and repetition, pitchers now lean on sophisticated tools and technology to burnish their arsenals and optimize their spin profile. Catchers have chipped in too, turning subtle positional and glovework adjustments into an avalanche of additional strikes on balls near the edges of the plate.

Hitters, meanwhile, spent the decade trying to play catch up. Strikeouts have climbed 5% in the past 10 years. Alongside, the league batting average has plummeted from .251 down into the .230s over that span. An industry-wide emphasis on steeper swing planes did fuel a surge in home runs, but even these gains are somewhat superficial, buoyed as they are by the juiced ball. Even with the recent crackdown on sticky substances, pitchers remain dominant.

Nobody ever stays ahead for too long in baseball though, and if you turn toward the farm, there are signs of life on the offensive side of the game. They’re not necessarily reflected in the numbers — most minor league circuits have more strikeouts and fewer dingers than the majors — but league stats bely real differences in how teams and hitters are preparing for battle against a modern pitcher’s arsenal. These gains are not spread equally across the league. Rather, the clubs that have most successfully invested time and resources into combatting high-spin fastballs at the top of the zone and a steady diet of breaking balls everywhere else have pulled ahead from the pack.

It starts in practice. The days of a coach lobbing BP from 40 feet away two hours before a game aren’t gone exactly, but progressive teams are increasingly finding better ways to develop hitters than a traditional batting practice session. The pitching machine, long out of favor among hitters at all levels of baseball, has become a vital part of a modern training regimen. Read the rest of this entry »

What is the first thing that comes to mind when you think about Aaron Bummer? It’s an odd question I know. For many, the answer might not be a whole lot besides the fact that he has an amusing name. He is a reliever, after all; given his role, he’s not the most recognizable player. For the initiated, however, the first quality that comes to mind at the mere mention of Bummer is likely his supreme ability to generate groundballs. Bummer’s has been in the majors since 2017; in five seasons, he has posted groundball rates of 54.4%, 61.2%, 72.1%, 68.4% (I will note he only threw 9.1 innings in 2020), and 73.7%. Over that time frame, he ranks fourth in groundball rate among all pitchers who have tossed at least 50 innings.

The leading culprit behind his prolific groundball rates is his sinker. Sinkers have sharp downward movement that fade away from a pitcher’s glove-side. The downward movement, coupled with the pitch generally being lower in the zone, prevents hitters from squaring up the ball, instead impacting the upper-half, driving the ball into the dirt. This season, the average groundball rate for a sinker sits at 56.4% compared to 41.7% for all other pitch types. And Bummer has a great sinker, one that inspired a post from Devan Fink on these very pages last February. Devan demonstrated with a tidy model that Bummer’s sinker is an elite blend of velocity and arm-side and vertical movement, the perfect recipe for inducing piles of groundballs from the opposition. And Bummer’s sinker has remained excellent; in 2021, the pitch has a laughable 82.4% groundball rate. The pitch is so effective that it inspired its own profile from The Athletic’s James Fegan, which included an amusing story of Bummer picking up the pitch after watching Zack Britton pitch while the former dined at an Applebee’s.

Overall, Bummer has been an excellent reliever throughout his major league career. The White Sox signed him to a five-year contract prior to the 2020 season, with two club options tacked on to the end that can keep him on the South Side until 2026. Given the volatility of relievers, that’s quite the endorsement of Bummer’s skills and I find it difficult to fault Chicago for doing so. He has a career 3.23 ERA, a figure 26% better than league average when you consider the difficult confines of his home park. The park-adjusted FIP is just as impressive, sitting at 23% better than league average over 161.2 career innings. Read the rest of this entry »

The draft is in five days, which means that teams are beginning to gather in their respective war rooms to prepare. It’s an exceptionally busy and hectic time. Many clubs have already had smaller, regional meetings as well as private workouts for players, both en masse and of the individual variety. The magnets are all printed out and ready to go. It’s just time to line them up.

Small or Large?

Teams organize their war rooms in highly divergent ways, but the biggest current split revolves around just how big the room is in terms of attendance. Some teams only have crosscheckers and those with more senior titles attend meetings, while others bring in their entire scouting staff. During my time with the Astros, the team always conducted full-staff meetings, and the benefits were numerous and glaringly clear. Area scouts know these players better than anyone and have seen them more than anyone. They’ve talked to the player, and quite possibly the player’s family. They might have followed a college player since their high school days. They know their coaches and summer league managers. They’ve run into the player’s representative multiple times during the spring and had a few chit-chats with them. Even if theirs is not the most important pure talent evaluation (though it often is), the things area scouts bring to the table are immensely valuable. And beyond their considerable assistance throughout the entire draft process, there’s also the simple morale component. Area scouts have sacrificed their lives for six months. They’ve missed birthdays, anniversaries and little league games, recitals and parent-teacher conferences, and now they’re not allowed in the room? It never made any sense to me, and it feels like more and more teams are moving to an all-scout meeting, as they should. Read the rest of this entry »

By now, I’m sure you’re aware of Yasmani Grandal’s odd season. We’re approaching the All-Star Game, yet the veteran catcher still has an unbelievably low batting average (.177) to go along with a stellar wRC+ (131). The juxtaposition encapsulates everything useful or wrong about modern baseball, depending on whom you ask.

Regardless, it works because while Grandal does strike out a fair amount, he also walks just as often – at a league-leading rate, in fact. But enough about Grandal. This is all a set up, because really, I want to talk about Christian Yelich. Why is he relevant? Yelich is one of two hitters (min. 150 PA) this season to have both a strikeout and walk rate above 20% – you can guess who the other is. Grandal’s season is, indeed, weird. But under the radar, Yelich is showcasing the same skills necessary for one, albeit without the hideous BABIP.

Focusing on the more positive rate first, it appears that Yelich’s monstrous walk rate is thanks to an ability to lay off unattractive pitches; his chase rate this season ranks in the 98th percentile per Baseball Savant. But here’s what piqued my curiosity. The other day, I stumbled across an article in Reviewing the Brew that suggested Yelich is seeing fewer pitches in the zone since last season. While true in the aggregate, looking at 2020-21 as one chunk prevents us from unearthing a notable truth. Let’s get to the bottom of it. Below is a rolling average graph showing Yelich’s zone rate over time, beginning a couple of years ago:

Consider the roller coaster ride. Before his transformation into a destroyer of baseballs, Yelich saw an above-average rate of strikes. That rate remained stable into his 2018 MVP campaign, perhaps because pitchers were caught off-guard by his late-season tear. The following year, though, they got the memo. In response to Yelich’s newfound might, the graph illustrates how pitchers began to shy away from the zone.

So far, so sensical. What’s interesting, however, is that the downward trend continued into 2020, despite Yelich battling through an extended slump that resulted in the worst season of his career by wRC+. At the very least, he seemed to take advantage of the increasing abundance of balls. As Tony Wolfe pointed out last year, Yelich effectively turned into Joey Gallo by cutting down his swing rate from 45.2% in 2019 to 34.6% in ’20. Unfortunately, his whiff rate – even against in-zone pitches – trended in the wrong direction, pushing up both walks and strikeouts.

Now it’s 2021. As I alluded to earlier, Yelich is still a patient hitter, and his 38.2% swing rate also suggests that he’s retained most of his 2020 self. The difference? His zone rate (48.0%) has skyrocketed this season, to the point where it’s similar to that of previous years (50.8% in 2018).

More strikes, but with the same passive approach – that seems like a recipe for disaster. But as of this writing, Yelich possesses the highest walk rate of his career. He’s managed to shave off a bit of his strikeout rate, too. That’s been possible because of how pitchers have allocated their extra strikes. Here’s a plot of Yelich’s yearly zone rate since 2017 by count type (ahead, even, or behind), from which we can gain some insight:

When Yelich is ahead in the count this season, his zone rate hasn’t seen a significant increase. Maybe pitchers are reluctant to challenge him – their escape is via a surefire strike, which Yelich has crushed multiple times in his career. It’s better to nibble around the edges, I suppose. Elsewhere, though, pitchers have caught on. The strikeout totals aren’t that hideous because Yelich’s contact rates have rebounded somewhat, but they’re still a few ticks below their pre-pandemic norms.

It’s a problem. More than ever, Yelich is having a difficult time defending himself against a barrage of strikes in unfavorable situations. Sean Doolittle, seemingly aware of this, threw a fastball down the middle against Yelich for… strike three.

Look at that smirk. He knows what he did!

But besides that example, how has Yelich responded overall? Compared to 2020, his swing rates are up across all counts. That’s good when he’s behind, and not as good when he’s ahead, though it could be that he’s targeting obvious strikes. Either way, Yelich is earning his walks. Looking at the numbers, however, I began to wonder – should Yelich become even more aggressive when behind? His swing rate in those instances is up, sure. But at 39.8%, it’s still lower than the 48.2% he posted in 2018, the year when he last saw a similar rate of strikes.

Let’s try and evaluate Yelich’s swing decisions using basic game theory. Consider a showdown between him and a pitcher with the count 0-and-1. What should each player strive to accomplish? For the pitcher, the best-case scenario is reaching 0-and-2. Since the start of the Statcast era, batters have recorded a .357 wOBA on 0-and-1; with an additional strike, that number drops precipitously to .166. Missing the zone en route to 1-and-1 isn’t as bad one might think, as batters pick up just 17 points of wOBA. It’s no wonder they’re considered behind.

On the other end, Yelich’s utmost goal is to avoid reaching 0-and-2. But to swing or to take, that is the question. Swinging seems like the most logical option, but there’s a good chance Yelich will end up whiffing or fouling off the pitch. Taking a strike isn’t the end of the world, but there are also obvious balls a hitter should never go after. And what about the borderline pitches that could go either way? Hitting is hard!

Amidst a hairy situation, here’s what I did. Based on Yelich’s contact, whiff, and foul rates this season, I calculated the average value of an in-zone swing in terms of wOBA, as well as an out-of-zone swing. The value of taking a strike or ball was based on the count-based wOBAs I described earlier. With these numbers, I was able to construct a two-by-two payoff matrix, with each cell containing the wOBA loss/gain of the pitcher (left of the comma) and the batter (right of the comma) that’s dependent on the actions taken:

For example, swinging at a strike would net Yelich 38 points of wOBA and lose pitchers the same amount. The latter are offering Yelich a strike 39% of the time in 0-and-1 counts. But is this optimal? For our sake, let’s say optimization means pitchers throw strikes at a rate that makes Yelich indifferent to swinging or taking. In other words, equalizing the payoffs robs him of a preference. Do the math, and it turns out the equilibrium point for pitchers is 35.5% strikes – quite close to their actual rate.

We can also find an equilibrium point for the hitter, Yelich. This time, it’s a matter of making sure pitchers are indifferent to throwing a strike or a ball, and the math suggests Yelich needs to swing 58.6% of the time in pursuit of that goal. Sounds too high? It probably is: I sorted all 0-and-1 pitches into simple strikes or balls, but as mentioned earlier, the reality is that a fair number of balls are flat-out uncompetitive pitches. Disregard them, and Yelich’s ideal swing rate is deflated. Even if we conservatively estimate it as 50%, however, it’s still a far cry from Yelich’s actual swing rate of 39.3% in 0-and-1 counts. Small sample caveats apply – he’s seen 84 of them so far this season – but there’s potential evidence that Yelich is missing out by letting strikes pass by.

Here’s an easier way to think about this. After factoring in zone rate, Yelich is expected to lose 50 points of wOBA by swinging. Taking a pitch loses 66 points, also bad, but which one is the lesser of two evils? You certainly wouldn’t want to swing every time, but faced with these payoffs, swinging a majority of the time makes sense. The math bears out our intuition.

For fun, I repeated the process using Yelich’s ridiculous 2019 output. Ready? To neutralize Yelich, pitchers needed to throw strikes roughly 20% of the time! Nobody would have followed that advice, of course, but it goes to show how terrifying Yelich was. He crushed pitches in the zone. He crushed pitches outside the zone, too, even when behind in the count.

It’s the version of the slugger we lament the disappearance of. But all things considered, it’s been a rough two-or-so years for Yelich. His 2019 campaign came to a premature halt after a knee injury, which then segued into a truncated, strange 2020 season. Mere days into the current season, back issues sent Yelich to the Injured List, where he remained for a month. Expecting him to attack the ball with his former authority is a bit unreasonable. And arguably, Yelich’s reluctance to swing is a precaution against re-aggravating his back.

But as far as adjustments go, raising his aggression to match that of pitchers, who are adhering to both a new and old book on himself, is a simple one. As Yelich recuperates, the various components of his game are likely to come together. It’ll be interesting to observe how he and opposing pitchers adjust against each other over the course of an entire season, engaging in a dance of zero sums. How high will Yelich’s zone rate climb? At what point does he swing enough for pitchers to change course and offer more balls instead? This piece’s title suggests the book on him is fixed. In reality, it’s constantly being updated.

We’re now five years into the Statcast era, and with that has come a good base of knowledge and an understanding of what small sample events are significant or beyond noise. Alex Chamberlain recently provided a wonderful example of this type of analysis; I encourage you to read that to get a feel for what I’m going to be talking about. But where Alex and Connor Kurcon covered the values of hard-hit balls at extreme launch angles and extreme exit velocity at given pitch speeds, I want to cover foul balls and what we can — or maybe can’t — learn at the extremes.

Any quick look at the Statcast leaderboard will show you that Yermín Mercedes has a max exit velocity of 116.8 mph, good for ninth best in baseball this year. That’s an incredible feat for any player, but what criteria do we want to set when determining a max? We’re ultimately seeking to measure raw power output, so maybe we should be more inclusive to all batted ball events. If we include foul balls, Mercedes would suddenly have the sixth-highest max exit velocity in baseball at 117.7 mph.

I encourage you to listen to that clip with sound, because the play-by-play commentary is all we have as to where the ball landed.

That 0.9-mph jump might not mean much, but there’s more to it once you consider both the rarity of the batted ball and the fact that we have a number on it in the first place. There’s a wide acceptance of all stats derived solely from launch angle and exit velocity, but you should consider the importance of spray angle. In the same way that both Alex and Connor talked about abnormal exit velocities in the context of a pitch speed or launch angle, something similar should be noted when thinking about the spray of the ball.

To understand this relationship, it’s important to see the spray angle at which each player generates their max EV:

Read the rest of this entry »

Jacob deGrom is on another planet right now. You don’t need me to tell you this, but it’s fun to just marvel at his stats. Through 10 starts, deGrom has a 0.56 ERA, a 46% strikeout rate, and a 4% walk rate. He’s produced 3.7 WAR, which is nearly a half-win better than the next-best pitcher, Corbin Burnes, who has “merely” put up 3.3.

deGrom is quite possibly in the midst of one of the best pitching seasons in baseball history, particularly on a per-inning basis. Pedro Martinez’s 1999 campaign currently holds the single-season pitching WAR record at 11.6, and though deGrom almost certainly won’t hit that mark, he’d blow it away if he pitched the same number of innings at his current rate. Give deGrom Martinez’s 213.1 innings, and at this pace, he’d put up 12.3 WAR. Say what you will about injuries and starting pitching workloads in this era, but that’s just a primer on the level of dominance deGrom has reached so far in 2021.

So if you’re a hitter stepping in against deGrom, how in the world do you get a hit off this guy? Batters are slashing just .121/.152/.220 against him, good for a .163 wOBA allowed. That’s the best mark among the 294 pitchers with at least 100 batters faced this season, and deGrom has more than doubled that threshold (223 TBF). If you’re hitting against deGrom, you’re lucky if you just put the ball in play, let alone get on base.

Is there an alternative strategy that works here? deGrom is raking up all of these strikeouts — without allowing virtually any walks — while boasting the seventh-lowest Zone% in baseball. Hitters are flailing against pitches that aren’t even strikes anyway: 60.5% of the time, deGrom is throwing the hitter a ball. If you’re in a two-strike count, he’ll throw you a ball 64.5% of the time, putting him in the 91st percentile in O-Zone%. Read the rest of this entry »

About a month ago, I wrote about Jack Flaherty and looked at his increased reliance on both his fastball and his slider. I posited that through his first seven starts, Flaherty had effectively been a two-pitch pitcher, with the aforementioned combination of pitches making up about 80% of his total pitches. (His curveball was his third-most used pitch, thrown sparingly at about a 13% clip.)

To investigate if this constituted a negative development and could account for Flaherty’s reduction in strikeouts relative to his career norms, I conducted a series of analyses. I grouped pitcher seasons from 2010-20 and looked at the number of pitches each pitcher had with a usage over 15%. This was somewhat arbitrary; I chose the 15% cutoff so pitchers with mixes like Flaherty’s in 2021 would appear in the bucket with two pitches. I then took each bucket and looked at the group’s strikeout rate, walk rate, FIP-, and WAR per 180 innings pitched. I found that between two, three, and four pitches, there was virtually no difference in any of the measures; the strikeout and walk rates were within a percentage point, as were the FIP- figures, while the prorated WAR numbers were within hundredths of a win. Next, I calculated the third time through the order (TTO) effect for pitchers in each bucket. To my surprise, there again was little difference between the pitcher buckets. My hypothesis was that two-pitch pitchers would struggle to get through the order as effectively as their peers who utilized more pitches. But based on my cutoffs for a relevant pitch (15% usage), this did not seem to be the case.

From there I concluded that Flaherty leaning on his fastball and slider more was not inherently bad; there seemed to be no evidence that being a two-pitch starter was inherently detrimental to striking out batters, preventing runs, and turning over a lineup on more than one, two, or three occasions.

But upon further reflection, I was dissatisfied with my process in arriving at this conclusion. The basis for my dissatisfaction was that my criteria for determining whether a pitcher was a two-pitch pitcher or a pitcher with three to four credible offerings. I chose the criteria, as I explained above, based on the tendencies of a single player I was interested in and in a way that would fit the narrative I was trying to tell. I also felt (anecdotally) there had been an influx of pitchers in the majors who have found success by primarily relying on two pitches; some of those pitchers happened to represent clubs the public deems “smart.” Thus, two-pitch starters were not actually more flawed than their peers with more diverse repertoires.

I will address the latter part of this line of thinking later (spoiler: it is extremely flawed) but this is just how I was trying to rationalize my findings. I have seen the performances of Luis Patiño and Shane McClanahan in 2021 and Tyler Glasnow last year (he added a slider this season) in Tampa with two pitches and thought the Rays may be on to something. Same for the Astros and Framber Valdez, Cristian Javier, and Lance McCullers Jr. (until this year, when he also added a slider). Two of the most surprising break-through pitchers of the past two-plus seasons have been Kevin Gausman and Lucas Giolito, both of whom rely primarily on a fastball/offspeed combination (for Gausman, the pitch is a splitter; for Giolito, it is a changeup). Dinelson Lamet is another pitcher with exceptional results (when healthy) relying only on a four-seamer and slider. As I mentioned above, this is all anecdotal evidence backing up a potentially faulty conclusion. There is no empirical support here. This is not the most rigorous approach to research.

That led me to redo my analysis, this time with more rigor in classifying the “two-pitchedness” of a player. Before I get into my methodology for this determination, I would be remiss if I did not at least introduce the main concept I am trying to measure: the third time through the order effect (which I will denote as TTO for the remainder of this piece). This is a phenomenon that has played a massive part in determining pitching roles and deployment in this era of major league baseball. It consists of the degradation of pitcher performance as he moves through the opposing lineup. No matter how you measure it — wOBA allowed, RA9, ERA — the pitcher population pitches worse the second time through the order compared to the first and the third time through the order versus the second. Generally, the effect is measured relative to the first time through the order. Since I will be using wOBA allowed in this piece, that means the second time through the order effect is the difference in wOBA allowed for the second and first time through the order and the third time through the order effect is the difference in wOBA allowed between the third and first time through the order. For some more background on the subject, I would recommend this piece at Baseball Prospectus by Mitchell Lichtman, which was my introduction to the phenomenon. More recently, Rob Mains did a multi-part series on the TTO penalty for BP. I would also recommend these two articles from Chris Teeter at Beyond the Boxscore; the first link measures the TTO for groundball versus fly ball pitchers and the second gauges the TTO by the type of secondaries a pitcher employs.

Now, onto to my analysis. First, let’s walk through how I grouped pitcher seasons this time around. For every pitcher season from 2010-19 (I threw out the shortened 2020 season) where the pitcher in question threw at least 100 innings, I looked at the percentage of pitches he threw for each pitch type. All the pitches were ranked in descending order based on their usage. I pulled the top two most used pitches for each pitcher and added their usage together. The sum of the usage of the top two pitches was my gauge of the “two-pitchedness” of that pitcher season. To give an example, Walker Buehler’s two most used pitches in 2019 were his fastball and slider. The former he threw 53.2% of the time and the latter he threw 14.2% of the time. Add those two figures together and you get 67.4%. That combined number was the figure I was concerned with for each pitcher season. A pitcher who only has two credible offerings will have a value close to 90%. Pitchers with the most egalitarian mixes will be down towards 50%. So instead of using an arbitrary cutoff to gauge whether a pitcher was a two-pitch pitcher, I used a continuous number that gives us a spectrum that’s not biased in any way (unlike my analysis in the Flaherty piece).

I bucketed the combined usage of the top two pitches in increments of 10 percentage points. All players with a combined usage of their top two pitches greater than 50% and at most 60% were grouped together, then greater than 60% and at most 70%, etc. Note that we are dealing with pitchers who threw at least 100 innings in a season. This means we are considering starters and, in recent seasons, “bulk” guys or pitchers who appear after openers and are tasked with starter-level workloads without the designation of pitching as a starter.

With the pitchers bucketed I went to pitch-by-pitch data from Baseball Savant. Each plate appearance in each regular season game was given the designation of how many times that pitcher faced that spot in the batting order. I appended the information about the pitch usage bucket the pitcher fell into and then collected the data for each bucket.

Before I get to the TTO figures, let me show you the information I described towards the beginning of this article about the performance of pitchers in each bucket, now with the refined pitcher designations:

For the rest of the piece, I am going to neglect the bins with so few players because the generalized results in those bins lack any signal given the size of the sample of pitchers in those buckets. Interestingly, it seems pitchers up to 90% combined usage of their top two pitchers performed best. They tied for the highest strikeout rates and posted the lowest walk rates, lowest park and league adjusted FIPs, and the highest WAR accumulation rates of all the relevant bins. All of these figures steadily decrease as the pitch mixes become less concentrated in the top two pitches.

Case closed! We shouldn’t care if a pitcher throws a useful third and/or fourth pitch, right? I will point out that I made this point in my Flaherty piece. But this is the incorrect conclusion. The pitchers in the 80% and up to 90% bucket faced the fewest batters per appearance, followed by the pitchers in the next lowest bucket. This means that these pitchers are being pulled earlier and do not have to combat the second or TTO penalty as often as the rest of their peers and suffer a degradation in performance. Managers and front offices have realized this effect and naturally have made a conscious effort to pull these types of pitchers before the opposition gets too comfortable in the batter’s box.

So pitchers with only two heavily used pitches post better results than those who leverage more offerings, but we know those performance indicators are biased in favor of those two-pitch pitchers. This performance bias presents itself with the TTO effect, which I calculated for the buckets in the table above.

The second time penalty is the wOBA allowed difference between the first and second time through the order and the last column is the TTO penalty. From the pitcher’s perspective, positive wOBA figures are disadvantageous because this indicates hitters are performing better.

The results here are stark. There seems to be no signal in how well a pitcher performs the second time he pitches through a lineup based on his propensity to throw his top two pitches. The TTO penalty, on the other hand, steadily increases from the lowest bucket in this set to the highest bucket. For pitchers who only use their top two pitches up to 50% of the time, the TTO penalty is worth just 18 points of wOBA. By the time we get to pitchers who are effectively throwing two pitches, the TTO penalty almost doubles relative to the lowest bucket, ballooning to 33 points of wOBA. The magnitude of the TTO penalty increases steadily among the buckets. The penalty for the second bucket (more than 50%, at most 60%) is four points higher than the lowest. The third is three points higher than that, while the fourth is four points higher than the third, and finally the last bucket is four points higher than the third. This is almost a perfectly linear trend. Adding pitches clearly gives pitchers more viable options to eat up innings and go deeper into games. That is not to say pitchers with broader repertoires do not suffer the consequence of the TTO penalty; instead the magnitude of the penalty is muted relative to their peers with arsenals concentrated in just a couple of pitches.

Along these lines and with the TTO penalty results on hand, I tried to determine if adding a pitch in a given season would improve a pitcher’s ability to get through a lineup by dampening the TTO penalty. I took two approaches. The first was more restrictive, where the new pitch in question could not be thrown at all in the season prior. This meant that I took every pitcher season from 2010-19 (with the same 100 innings minimum restriction as before) and for every pitch that pitcher threw, I cross-checked with their prior season and noted if they threw the pitch at all. If the answer to that query was yes, then the pitcher was not marked with utilizing a new pitch. Correspondingly, if the answer to the query was no, I marked the pitcher as having a new pitch. The restrictive nature of this querying and flagging of pitchers and pitches made me skeptical that the results would be relevant on account of the small group of pitchers who add a completely new pitch after not using it the prior year. My skepticism was borne out in the results (Note: a previous version of this table was the exact same as the table you will see later in the article. That mistake has been rectified and the following has the updated results).

In the cases of the second time through the order penalty and the TTO penalty, there is basically no change across seasons when adding a new pitch from scratch, with changes on the scale of single points of wOBA, which is noise. There is also no discernible difference between those who add a new pitch and those who do not, based on this criterion. However, the population of pitchers who truly add a new pitch, one they did not throw prior to the season at hand, is very small.

So I changed the definition of what constituted a new pitch. For the second go around, a new pitch was one the pitcher threw at least 10 percentage points more than the season prior. Yes, 10 percentage points is arbitrary and yes, I talked about arbitrary cutoffs at the start of this piece. But I would offer that the cutoff had to be set somewhere and my choosing of the cutoff was not influenced by the pool of pitchers I was analyzing. Also, I realize that my new criterion does not technically denote a “new” pitch like the first. But the spirit of this portion of the investigation is to flag pitchers who add a pitch the opposing hitter must account for differently in a plate appearance compared to how they would have approached the pitcher in a prior season. So, if a pitcher goes from throwing a pitch 5% of the time in year n-1 to 20% of the time in year n, that is a fundamental change in their repertoire that will have massive ripple effects on how they are scouted and what a hitter is looking for in any count.

The results of my second query were more promising but hardly groundbreaking.

Pitchers who added a new pitch by this criterion shave about two points of wOBA from their TTO penalty while the rest of the population adds about five points year-over-year. One possible explanation for this seven-point wOBA discrepancy is that without making a fundamental shift to your repertoire, major league hitters can get a better handle on you the following season, yielding a more substantial TTO penalty. Another explanation, which goes hand in hand with the fact that pitchers who do not meaningfully add a new pitch actually perform slightly better the second time through the order, is that the population of pitchers who did not add a new pitch includes pitchers who decreased their usage of certain pitches. So this population includes pitchers who became more of a two-pitch pitcher season over season, thus choosing to lean into their best pitches more.

As I said at the top, these two-pitch pitchers perform better on a rate basis but do not pitch as deep into games and suffer harsher TTO penalties. This, at least to me, is the most likely explanation for pitchers who would fall under the designation of the first row of the table improving the second time they go through the order but feel the effects of a more robust TTO penalty. On the flip side, pitchers who make a pitch a more substantial part of their arsenals worsen when they go through the order the second time but make up for it by dampening the TTO penalty.

Is this a worthwhile tradeoff? Would you rather have a pitcher more dominant on a per plate appearance level but who taxes your bullpen more? Or would you want your starter/bulk guy to go deeper into the game? It obviously depends on your roster construction and how often your bullpen has been used leading up to a game, but this is a question front offices and field staff constantly juggle throughout the season and in the offseason when building their teams.

Close to 3,000 words later, what have we learned? First and foremost, when attempting to measure anything or test a hypothesis, upon the conclusion of the research it is important to reflect and ask critical questions of how you approached the problem at hand. After my initial study into the viability of two-pitch starting pitchers centered around Jack Flaherty, I concluded that two-pitch pitchers were just as effective on a per pitch basis and that they suffer no additional TTO penalty. Therefore, I surmised, rostering these types of starting pitchers should have no detrimental effects on how you build your roster and are not a reason to be skeptical of a pitcher as a viable option to churn through an opposing lineup. The issue I found was that my definition of a two-pitch pitcher was flawed, based on an arbitrary cutoff to try to diagnose Flaherty’s lack of strikeouts in the early going.

When I eliminated the arbitrary cutoff and used a more continuous definition of how much a pitcher relies on his top two pitchers, I found that pitchers with more limited repertoires were a little more effective than the rest of their peers, but did not go as deep into games. Furthermore, they suffered a much harsher TTO penalty, which is most likely the explanation for those pitchers not facing as many opposing hitters.

The idea that pitchers with only two viable pitches are better suited for short starts, bulk work, or high leverage innings is not a groundbreaking finding, but I hope putting some empirical justification behind this idea is useful and this approach relatively new (at least on the public side). This confirmation of what many evaluators believed to be true should help us ask critical questions about how players should be deployed and developed, and what sorts of pitchers a roster requires. If the Rays invest in pitchers like Shane McClanahan and Luis Patiño, how should they be used and how does that affect Tampa’s roster? Well, it seems they are following what the research demonstrates: roster a deep bullpen and use these pitchers in three to five inning stints. The same concept holds true for the Astros and Cristian Javier and Framber Valdez or the Padres with Adrian Morejon, Ryan Weathers, and Dinelson Lamet.

Another essential part of this calculus is how we should be evaluating players in the minor leagues or amateurs in the draft. The starting viability of players like Garrett Crochet and Max Meyer has been called into question in recent draft classes; the same goes for Sam Bachman in this upcoming draft. Binning these types of pitchers — with high-end fastball velocity, wipe-out breaking pitches, and a history of starting — as starters or relievers seems foolhardy. Instead, we know pitchers with this skillset can effectively get through a lineup twice but more than that and the manager is playing with fire. Given this breed of pitcher’s effectiveness per plate appearance, actively avoiding acquiring pitchers with only two viable pitches is narrow-minded. Instead, if they make it to the major leagues, teams should be trying to supplement these elite talents with other pitchers who mesh with the roles required to maximize the skills of a Max Meyer or Garrett Crochet type pitcher.

I do not believe this is lost on much of the league. I am merely suggesting two-pitch starting pitchers can be excellent players in the correct environment. But given a TTO penalty almost twice that of starting pitchers with more diverse arsenals, two-pitch pitchers need to be monitored closely. If the league allows teams to carry as many pitchers as they would like, two-pitchedness and flame throwing bullpens are here to stay. Until the rules on pitcher limit take affect, with the correct usage limited pitch mixes will continue to be valuable assets to major league clubs, provided those two pitches are high-end offerings.

One of my favorite things about attending a live baseball game is how it sounds. Sure, the pops and cracks of leather and wood on the field are comforting in their own right, but what I’m really talking about is the chatter. The constant din of anonymous talkers throwing out well-researched stats, or strongly felt opinions on pitchers’ hair length, or two-notches-too-loud questions about where the Bud Light guy is. And as much as I enjoy the ambient noise of a major-league ballpark, for my money, there is no baseball chatter that compares to that found in the stands of a high school game.

At the end of May, I attended my first live baseball game since 2019, a matchup on the South Side of Chicago between Marist High School and Marian Catholic. Heading into the game, Marist had the best record in Illinois, thanks in part to Noah Smith, their toolsy infielder, and our top-ranked high school prospect in the state. Also on the field was Smith’s Area Codes teammate and fellow Louisville commit, Eddie King Jr., playing in the outfield for Marian Catholic. But in the bleachers along the first base line, the chatter wasn’t about whether Smith would ever eliminate the sway in his swing and stabilize his head to more consistently identify breaking balls, or how hot a bat King was swinging after he smashed a double off the left-field wall (he had homered in the game the day before, also against Marist). Instead, I found myself seated in between a group of teens who had googled the team’s roster because one of them was pretty sure she’d sat next to one of the outfielders in Freshman Spanish, and a mom who spent the entire game playing defense against her toddler, who was intent on pulling on the cord coming out of the camera she had perched on the railing to record her older son’s performance on the field.

After the game, there were hugs and pats on the back from the parents in the stands, and awkward giggles from the group of girls I’d been sitting by, none of whom seemed keen on actually approaching any of the players. Marian Catholic won 9-7, issuing Marist its first conference loss of the season (and third loss overall), and knocking them down to second place in the state. If anyone in the stands noticed, they hid their disappointment well. But regardless of whether or not the audience at this mid-week, mid-afternoon high school game was aware of the stakes of the game itself, it was clear how much they cared about the players on the field. The sense of community was palpable. Even as an outsider, I felt like I’d attended an event that meant something to my fellow spectators – something specific, and unrelated to baseball. Read the rest of this entry »