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Last week, I dug up an old concept: expected home run rate. The idea is deceptively simple: assign some probability of a home run to each ball a batter hits in the air, then add them up. It tells you some obvious things — Fernando Tatis Jr. hits a lot of baseballs very hard — and some less obvious things — before getting injured, Aaron Judge had lost some pop.

One question that many readers raised — reasonably so! — is whether this expected home run rate actually means anything. The list of over-performing hitters was full of sluggers. How good is this statistic if it tells you that good home run hitters are, in fact, not as good as their home runs? Sounds like a bunch of nonsense to me.

In search of truth — and, let’s be honest, article topics — I decided to do a little digging. Specifically, I wanted to test three things. First, how stable is expected home run rate? In other words, if a player has a high expected home run rate in a given sample, should we expect them to keep doing it? If the statistic isn’t stable, what’s the point?

Second, how does it do at predicting future home runs? In other words, does an expected home run rate in, say, July predict what will happen the rest of the year? It’s also useful here to see if expected home run rate (from here on in, I’ll be calling this xHR% for brevity) outperforms actual home run rate as a predictor. If xHR% doesn’t do a better job of explaining future home runs than actual home runs, what use is it? Read the rest of this entry »

Dylan Cease has a simple calling card: a four-seam fastball that he throws in the upper 90s. Every prospect evaluation of Cease centered on the heater, a bludgeon he would use, the theory went, to leave hitters with no good choices. He backed it up with a curveball and a developing changeup, but those were the backup dancers; the fastball was the star everyone came to see. There were questions about whether he’d be able to make the whole package work, but if it did, the heater would be the reason why.

Nine starts into his sophomore season, however, things haven’t gone according to plan. Cease’s 15.4% strikeout rate is the fourth-lowest among qualified starters, ahead of only Mike Fiers, Antonio Senzatela, and teammate Dallas Keuchel. The White Sox probably hoped Keuchel would help mentor their pitching staff, but uh… not like this. On the other hand, Cease is running a 3.33 ERA, better than team ace Lucas Giolito. Huh?

In an even stranger development, Cease’s fastball appears to be the culprit behind his poor strikeout rate. Though it hasn’t lost any velocity — his 393 four-seamers this year have averaged 97.4 mph — the pitch simply hasn’t missed any bats. Here are the 12 pitchers with the lowest whiff-per-swing rates on their four-seamers, as well as their average velocity:

That’s not a list of bad pitchers. It is, however, disconcerting to see a fastball-first power pitcher sharing space on a list of contact-heavy fastballs with literally Zack Greinke. Cease has an absolute cannon, but he isn’t missing any bats with it. Read the rest of this entry »

Last year, I came up with a simple idea: estimate home runs based on exit velocity. That sounds pretty straightforward, and it mostly is. For example, here are your odds of hitting a home run at various exit velocities when you put the ball in the air in 2020:

Of course, some caveats apply. I’m only looking at batted balls between 15 and 45 degrees, and the sample size is still small. But for the most part, and excluding the vagaries of that small sample, the conclusion makes sense. Hit the ball harder, and you’ll find more home runs.

Of course, real life is notoriously fickle. Sometimes you mash the ball and it’s a degree too low, or you hit it to the wrong part of the ballpark, or a gust of wind takes it. Sometimes you play in Yankee Stadium and get a cheapie, or smoke a line drive that leaves a dent in the Green Monster. Sometimes you make perfect contact, and it’s at 15 degrees instead of 25 so it’s a smashed single to right instead of a bat flip highlight.

Wait — hit it at the wrong angle? That seems like something in a batter’s control. It partially is, but I’ve chosen to exclude it for two reasons. First, I’ll point again to this excellent Alex Chamberlain article. You should really read it, but the conclusion is basically this: batters control exit velocity and pitchers control launch angle. That’s not exclusively true, and there are obviously fly ball and groundball hitters, but if you start giving batters credit for the exact angle of their batted balls instead of just generally saying “in the air” or “not,” you might be going too far.

Second, this way is simpler! Simplicity has value. Overspecify a model, and you can get very precise results that are also hard to interpret, or that depend heavily on small fluctuations in initial conditions. That’s not to say that such a model is a bad idea — merely that it’s not strictly upside to add more and more gadgets and whizbangs to it. You also risk losing the signal you’re looking for, which in this case is the ability to absolutely hit the snot out of the ball, sending it skyward at stupid speeds. Read the rest of this entry »

Here’s a sentence you can find, on this very website, about Nelson Cruz: “Age and injuries have sapped Cruz’s speed in the outfield… Cruz has always struck out more than the average player, but his walk rate has dropped back below average the last few seasons. Cruz also has a durability problem, only playing in more than 130 games once in his career.” The fact that an outfield position is even in consideration should give you a clue that this isn’t current, but what year would you guess? 2016? 2017?

Here’s a further clue: the next line was “His (last year) was of course shortened by a drug suspension, which adds its own peculiar twist to his projection.” Yes, this was his 2014 writeup, penned just before he signed with the Baltimore Orioles. If that feels forever ago, that’s because it was. It’s two Cruz contracts, and 26.1 WAR, ago. Whoops!

That’s no slight on Matt Klaessen, who wrote that fantasy profile. Predicting Cruz’s age-related decline is a yearly tradition at this point. Here we are, though, in 2020, and the decline is still nowhere to be seen. Cruz is hitting .343/.432/.685, good for a 193 wRC+, the fulcrum of Minnesota’s offense. Naturally, then, I’m going to predict that Cruz is in for a decline… kind of. Read the rest of this entry »

The last time we saw Gerrit Cole in an Astros uniform, he wasn’t actually in an Astros uniform. He was, instead, in a Boras Corporation cap, ready to chart his own course through the league after a dominant run in Houston. When he signed with the Yankees, it felt almost preordained — one of the bright stars of baseball, either the best pitcher in the league or a close second, on the most storied franchise in the game. We get it — great players like the Yankees, and the Yankees like great players.

One look at the surface-level statistics will tell you that something hasn’t panned out in 2020. A 3.63 ERA? A 4.69 FIP? Thirteen home runs allowed in only nine starts?! He’s allowed a home run in each start, which is about as disastrous as it sounds. Heck, even his record tells you something is up; he’s 4-3 this year on an underachieving Yankees team, and while wins and losses are silly contextual statistics, Cole went 35-10 the last two years. Something is clearly up.

Far less clear? What that “something” is. There are some easy ways pitchers fail, ones you can see from a mile away. They lose velocity, and their fastballs become newly hittable. That hasn’t happened to Cole, though, at least not really:

Starters can also lose feel for one of their pitches, and change their pitch mix to compensate. That hasn’t happened either:

Uh… maybe he’s the victim of a poor early-count approach. He’s throwing fewer fastballs this year to start batters off, but just as many pitches in the zone. He’s not doing it by throwing more curveballs and sliders in the zone, either:

In other words, Cole is throwing fastballs less often to start, but he’s making up for it by throwing them in the strike zone more often. Sounds dangerous. Are batters suddenly teeing off on him on 0-0? Nope! They’re actually swinging less than ever, and the whole thing is too small-sample to matter anyway. He’s getting to 0-1 54.5% of the time, in line with his dominant 2019. Next! Read the rest of this entry »

When we last checked in on our Out Of The Park Brewers experiment, the season hung in the balance. We had fallen two games behind the Pirates — that’s bad! — but were mere days away from welcoming Christian Yelich back from the Injured List — that’s good! The sprint to the end of the season figured to be a high-leverage thrill ride.

For about two days, that played out. On August 19, the Brewers hit a season-high 16 games above .500 and pulled within a half game of the Pirates. Yelich was back. Everything was coming together nicely. Then the team lost seven straight games while the Pirates went 5-2. Just like that, it was a 5.5-game deficit in the Central, with the Brewers and Philadelphia Phillies now locked in a dead heat for the second Wild Card.

How does something like that happen? Reasonably easily, to be honest. Not every playoff contender has a seven-game losing streak, but the margins are slim. Two of the games were one-run affairs, while another featured a seven-run meltdown in the ninth inning to snatch defeat from the jaws of victory. A 3-4 stretch would have looked extremely different than 0-7.

Things were still fine, though. The Pirates weren’t quite out of reach, and based on the fact that I called it a seven-game losing streak, clearly the team won the next day. Now the Wild Card race was a dead heat, and Yelich was settled in. Surely this would be a turning point. Read the rest of this entry »

For the last 15 years, Yusmeiro Petit has cast a spell over opposing hitters. He’s never thrown hard — his highest average fastball velocity was 89.6 mph in 2017, more than a decade into his career. He’s never been an All-Star, never received award votes. He’s been sketchy at times — his rookie season for the Florida (!) Marlins produced a 9.57 ERA. He didn’t pitch in the majors in 2010 or 2011. Through it all, however, he’s kept going, showed up and provided competent innings. He’s almost 36, and it feels like he might pitch until he’s 80.

That consistency is merely an illusion, however. When Petit first made the majors, he was pretty bad against lefties. Most righties get a little bit worse against left-handed batters; they strike out roughly two percentage points fewer opponents and walk roughly two percentage points more. Petit, on the other hand, turned into a pumpkin:

That split is through the end of 2017. I’m now going to do something that I strongly urge you not to do in your investigations of platoon splits — chop them up into smaller pieces. Since the beginning of the 2018 season, Petit’s platoon splits look different:

It’s a small sample, but I’m inclined to believe it. From 2008 (the beginning of pitch tracking data) to 2017, Petit threw his changeup to lefties 22.1% of the time. Since the beginning of 2018, he’s more or less doubled it, to 41.3%. Changeups are a righty’s best friend against lefties, so the improvement makes sense. Read the rest of this entry »

Two years makes a tradition: it’s now a ritual for the Marlins and Diamondbacks to make an intriguing trade leading up to the deadline. Last year it was Zac Gallen for Jazz Chisholm, and this year the Marlins are acquiring Starling Marte:

Caleb Smith, Humberto Mejia and one other from the Marlins to DBacks for Starling Marte, source tells The Athletic.

— Ken Rosenthal (@Ken_Rosenthal) August 31, 2020

When the Diamondbacks traded for Marte this offseason, they did so for two reasons. First, they wanted to make the playoffs. That one hasn’t gone according to plan; after starting 3-8, they briefly righted the ship at 13-11 but have since gone on a cold streak. They entered today at 14-21 and only a 9.9% chance of reaching the postseason per our playoff odds. Short seasons are tough: a cold spell can upset the best-laid plans.

The Marlins, on the other hand, came into the year as playoff longshots. After a surprising run following their COVID-induced layoff, however, they’re 14-15 and are currently in playoff position. We still don’t like their odds — we give them a 22.7% chance of holding onto a spot — but that’s the best shot at playing October baseball they’ve had in years, and Marte will help immediately.

But that’s not the only reason the Diamondbacks traded for Marte. He still has a club option for one more year at $10.5 million (it’s $12.5 million but with a $2 million buyout) after signing an extension with the Pirates. That made him more than a one-year rental; two years of above-average center field play for reasonable rates is an enticing package.
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Catcher valuation, like Maria, is a difficult problem to solve. The San Diego Padres took a stab at it on Sunday night, trading for Seattle backstop Austin Nola in a seven-player swap. Jake Mailhot took a look at the calculus behind that decision, which completely revamped San Diego’s catching depth chart while also sending a big-name prospect to Seattle, which Eric Longenhagen covered.

But that wasn’t the entirety of the deal — not by a long-shot. A.J. Preller tacked on a swap of relievers in much the same way you or I might grab a pint of ice cream at the grocery store — “Well, since I’m already here, I might as well get this.” Relievers Austin Adams and Dan Altavilla are headed to San Diego as part of the Nola deal as well.

You’ve probably heard Austin Adams’ name before. It might even be the right Austin Adams — there’s another righty reliever by the same name in the Twins organization. You might not know just how excellent he is though. In a short 32-inning stint in the big leagues last year, he blew the competition away, striking out 40% of his opponents. He also walked 12%, which isn’t great, and had surgery to repair a torn ACL last September, so it’s not like he’s peak Craig Kimbrel without the name recognition. But he’s seriously great.

Adams sports the classic origin story for a good reliever: the Nationals traded him away for pitching help. In 2019 (!), they sent Adams to the Mariners for minor leaguer Nick Wells. Roughly a week later, the Mariners called him up, and after a debut featuring all three true outcomes — three strikeouts, a walk, and a home run in five batters — he rounded into being their best bullpen weapon. Read the rest of this entry »