In the course of researching the haphazard nature of JP Sears’ fastball command for my blog Pitch Plots, I realized I was missing the answer to a fundamental question: Why does the ball go where it goes?

Specifically, I had no idea which variables determine the physical location where a pitch crosses home plate. My first guesses revealed nothing: a combination of velocity, extension, spin, and release height had no relationship to a pitch’s eventual location. If it wasn’t any of these factors, what could Sears change to throw his fastball to better locations?

I was missing the key variable: the release trajectory. Trajectory, as defined here, is not just release height and width but also the vertical and horizontal release angles of the pitch, which are not widely available to the public on a pitch-by-pitch basis.

The release trajectory, it turns out, explains nearly everything about the ultimate location of a pitch. Read the rest of this entry »

I won’t sugarcoat it for you, friends. It’s a tough time to be a major league starting pitcher. Their ligaments are under threat like never before. Their workloads aren’t far behind. For a variety of reasons, the old style of starting pitcher is quickly headed toward extinction and we’re transitioning to a new way of doing things.

That all seems like the obvious truth. But I decided to go to the data and make sure. As Malice of the Clipse (and yes, fine, Edgar Allan Poe) memorably said, “Believe half what you see, none of what you heard.” I’m not sure exactly where that leaves you, since I’m going to be telling you what I saw, but that’s an epistemological question for another day. Let me just give you the data.

So far this year, there have been 452 games, and thus 904 starts. Starters have completed 4,735 1/3 innings, or 5.24 innings per start, and they’ve thrown an average of 86.2 pitches to get there. They’ve averaged 94.1 mph with their four-seamers, yet despite all that velocity, they’ve thrown fastballs of any type just 54.9% of the time. This isn’t Opening Day starters, or anything of that nature; it’s just whoever has picked up the ball for the first pitch on each side.
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On Monday night, I had the privilege of attending a game in which the Reds’ best left-handed starter, Andrew Abbott, faced the Phillies’ best left-handed hitter, Bryce Harper, three times. Abbott got the better of Harper, who went 0-for-3 with a strikeout against the Cincinnati starter and 0-for-5 overall. But the qualities of each player got me thinking.

When Harper swings the bat, one of two things happens. In scenario no. 1, he squares it up and hits it so hard it causes bruising on the deceased ancestors of the workers who stitched the ball together at the Rawlings factory. Sure enough, Harper tagged Abbott’s teammates for three home runs just 24 hours later.

Otherwise, Harper misses it. He can miss it by a lot, in which case he just swings through it, or he misses it by a little. Those swings manifest themselves either in balls fouled straight back to the screen, or in fly balls that go straight up in the air and stay there long enough for the outfielder to take out his phone, and queue up Meat Loaf’s “Bat Out of Hell,” so the ball lands right at the climax of the second chorus. You know the part: “Like a sinner / before / the gates of Heaven / I’ll come crawling on back to you.” The loud one, like five and a half minutes into the song. Read the rest of this entry »

On Monday, I dove into Kevin Gausman’s fast and furious two-strike fastball approach. Last season, Gausman led the majors in terms of the velocity gap between his normal fastballs and his two-strike offerings, and he prospered with that approach. In 2022, however, he had the same juicy gain in velocity and was one of the worst pitchers in baseball with two strikes.

In that article, I mused that it was really difficult to know what pitchers were doing differently with two strikes. Short of using a stuff model, I said, trying to figure out relative pitch quality between two-strike fastballs and their early-count brethren wouldn’t work. Then I had an epiphany. We have a stuff model. We have two, in fact, one of which is entirely in-house. So like a kid asking for the keys to the candy store, I went to David Appelman and asked if I could get pitch-by-pitch stuff grades.

Now I have those! It turns out that running a giant data-focused baseball website comes with access to a tremendous amount of baseball data. I pulled every four-seam fastball thrown in 2023 and broke them into two categories for every player: two-strike counts and all other counts. Read the rest of this entry »

The proliferation of Stuff models has invariably pitted capital-S Stuff against command in terms of their respective importance to a pitcher’s success. If you had to choose one, is it better to locate well, or is it better to be filthy?

The answer to this question is why baseball is beautiful and delightful but also occasionally horribly frustrating. From Vicente Iglesias and Scott Powers:

Importance, in layman’s terms, means how relevant a variable is to explaining an observed outcome; reliability is how much we can expect a variable to repeat or be repeated. In baseball, we often talk about these ideas in terms of “descriptiveness” and “predictiveness.” This dichotomy illustrates the Catch-22 that forever propels baseball forward in all its uncertain glory: pitch location plays an outsized role in determining the outcomes we witness, yet we cannot expect to rely on it year over year. Meanwhile, Stuff is much more reliable next year — i.e., changes to a pitcher’s pitches in terms of velocity, movement, and release point tend to vary to a much smaller degree over time — but it plays a significantly undersized role in influencing actual outcomes this year. Brutal stuff. Why do we even bother? Read the rest of this entry »

Yesterday, I laid out a new method of quantifying depth that we’re looking into here at FanGraphs. It’s based on the idea that while our depth charts are a point estimate of how much each player will play, the real-life way things work is different. To mimic reality more closely, we’re experimenting with removing players from the depth charts algorithmically and rebuilding teams on the fly to see how they look without their best players. Yesterday’s article covers our methodology in great detail.

There’s one thing that I wanted to add to that article but couldn’t find the space for: more tables. There was one big giant table in there that showed each team’s winning percentage as we removed more and more players from their squad. But that’s just not a great way to look at anything – 300 numbers in a giant table is more information than our brains can easily process. I don’t have a lot of new information today, but I thought I’d slice that data up into more bite-sized chunks so you can look at it without your eyes glazing over. One quick note: All the tables in this article are sortable, so you can order them by whichever category you so desire. Read the rest of this entry »

In his recent piece about umpire accuracy, Davy Andrews noted that plate umpires correctly called 99.26% of heart zone pitches in 2023. When I first read that number, I didn’t think missed calls in the heart zone warranted any closer investigation. For most of us, ninety-nine point anything is as good as 100; you don’t spend much time worrying about the 0.01% of germs Purell can’t kill. Then again, if you were to consider the sheer amount of bacteria on your hands at any given moment, you might opt for a second squirt of sanitizer. A tiny percentage of a tremendous number is still going to be a pretty big number. The same is true for missed calls in the heart zone. There aren’t quite as many pitches in an MLB season as there are germs on your phone screen, but there are enough that a few tenths of percent of heart zone offerings still represents a pretty hefty figure. In 2023, plate umpires watched 381 pitches sail over the heart of the plate without signaling a strike. When you frame it that way (pun absolutely intended), it actually sounds pretty bad.

I wasn’t nearly as surprised to learn that plate umpires missed 428 calls in the chase zone last season. Offerings in the chase zone are designed to look hittable out of the pitcher’s hand. An especially talented catcher can make them look hittable as they reach his glove, too. Meanwhile, a batter might like to earn a few extra balls inside the zone, but he doesn’t have the same influence over calls as do his opponents. Besides, if a hitter recognizes that a pitch is coming for the heart zone, he’s not going to wriggle and contort his body in hopes of inducing a missed call – he’s going to swing. To that end, batters are much more likely to swing in the heart zone than the chase zone, which means that on a rate basis, umpires miss significantly more calls over the heart of the plate because there are fewer total pitches there that need to be called. While 381 and 428 are similar figures, batters took 2.4 times as many pitches in the chase zone as in the heart zone. Apparently, it’s harder than I thought to call strikes what they are. Read the rest of this entry »

One of the great perks of working at FanGraphs is that I get to discuss baseball with my equally obsessed coworkers. Obviously, this is the kind of job you don’t get into unless you love the sport. A lot of the time, that means we just end up nerding out over how much we enjoy some minor but cool thing, or perhaps discussing our favorite of the game’s idiosyncrasies. Sometimes, though, we come up with new ideas together, or one person’s passing fancy turns into another person’s brainstorm, and before you know it, something nifty and novel is happening.

That’s why I’m writing this article today. At the December Winter Meetings, a subset of us sat down for our annual let’s-talk-about-fun-baseball-problems technical meeting. David Appelman and Sean Dolinar ran things. Folks like Jeff Zimmermann and Dan Szymborski popped in at various points. Jason Martinez and Keaton Arneson had big plans for how to improve the site’s functionality. Those guys are great at building models, running websites — advancing the state of how FanGraphs (and ZiPS) works, basically. I like to make jokes and write articles about bunts, so as far as I can tell, I got invited because I’m good at coming up with bad but interesting ideas.

That said, this year one thing was on a lot of our minds: depth. I’ve written a lot about how well our playoff odds reflect reality. They’re pretty good! But there’s always been an obvious problem with them. They use static rosters, which means they don’t account for the fact that some teams are more vulnerable to injury or underperformance than others. Read the rest of this entry »

We will not be breaking new ground today. What you read in this article won’t change the way you understand baseball. However, it might help you to appreciate a few baseball players for who they are, and that strikes me as a noble goal. A couple weeks ago, Ben Clemens introduced Whomps Per Whiff, a stat that divides barrels by whiffs in order to show “how often you absolutely whomp the ball, as compared to how often your swing results in nothing but a tiny gust of air.” It was a remarkably simple way of looking at hitting, and the leaderboard featured some of the best hitters in baseball. It was also a fun article, and I agreed with several of its underlying premises:

• If there’s one thing baseball doesn’t have enough of, it’s statistics.
• Anybody can make up a statistic, as long as they have a dream in their heart and a copy of Microsoft Excel.
• It’s important that those statistics have silly names. That’s why I’ve been lobbying to have people pronounce wRC+ as “Work-Plus,” preferably in a Rihanna voice.
• The word whomp is decidedly fun.

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The introduction (and then reintroduction) of the designated hitter to the National League wasn’t the smoothest of rollouts. It was first brought about as a safety measure in the chaos of the pandemic-shortened 2020 season, designed to relieve unnecessary stress on pitchers who were already dealing with a disrupted preseason. Despite the best efforts of the Players Association, the DH was removed from the NL for 2021, as the league declined to implement it without getting something in return (in this case, a delayed and potentially shortened season). A year later, and more than two months into the lockout, as the league and the union battled through negotiations over the new collective bargaining agreement, it was announced that the universal DH would return for the upcoming season, this time indefinitely.

It was a difficult task for NL teams to prepare one way for one season and another for the next. Of course, any hitter can slot into the DH spot on any given night, but not every team comes with a player who can provide real value with his bat alone, and it takes time either to acquire or develop a player like that, or to build enough depth to overcome not having one. With the universal DH, NL clubs would need to get another 700 or so productive plate appearances from their rosters — that’s no small feat. Understanding this, let’s consider the state of the DH in the National League.
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