Article: Gausman Most Foul

[Davy Andrews]

Kevin Gausman has been pitching lights-out despite not missing bats. How is he doing it, and will he be able to keep going it?

Please allow me to drag you back down to this date one year ago. At that point, Kevin Gausman had made three starts and pitched just 9 1/3 innings. He had an 11.57 ERA, and lest you think he’d just gotten unlucky, his FIP was 6.17. He was bad, is what I’m trying to say, and it would take him a while to turn it around. Let’s return to 2025 now. Kevin Gausman has made three starts and he’s pitched 19 1/3 innings, 10 more than he had at this point last season. In his last start on Wednesday, he tore through Red Sox, allowing one unearned run over eight innings, striking out 10 and allowing just four hits and no walks. He’s 1-0. He's got a 2.33 ERA and 3.37 FIP. The skies are clearing and the birds are chirping and so on.

So is Kevin Gausman back? It really, really depends who you ask. For starters, that 3.37 FIP says that he’s probably been a bit lucky so far, and his 3.98 xFIP says so even louder. So much of baseball writing, especially early in the season, is just trying to figure out what’s actually going on. The sample sizes are small. The variances are huge. Gausman’s fastball velocity ticked back up in his first two starts, but it dropped way down on Wednesday. Were the first two games a mirage, or was it just that the third game took place on a really cold night in Boston? Nobody else’s fastball velocity was way down that night. Some things just aren’t knowable. All I can do right now is take you through the good and the bad.

One of Gausman’s big problems last year was that he stopped missing bats. In fact, his whiff rate has fallen in every season dating back to 2020.

Season	Whiff%	Percentile
2020	33.1	84
2021	31.4	83
2022	29.4	75
2023	28.9	70
2024	23.4	33
2025	21.3	9

That’s right, Gausman has been pitching so well this season despite the fact that his whiff rate is worse than 91% of the other pitchers in baseball. However, his 20.6% strikeout rate isn’t disastrous. It’s not that far below the league average. So why is his strikeout rate in the 41st percentile rather than the first percentile if he’s not missing bats? Is he getting lots of called strikes? Nope. His 12.3% called strike rate is the lowest of his entire career. But you know what he is doing? Kevin Gausman is leading all pitchers with a 25.6% foul rate. He’s not missing bats, and he’s not earning called strikes, but he is making people foul it off a lot. His 72.1% first strike rate is also among the best in baseball, which shouldn’t be surprising, since his 22.1% foul rate on those pitches is second in all of baseball (respect to Boston’s Richard Fitts’ who’s sitting just below 33% on those pitches).

How is Gausman earning so many foul balls? It’s mostly about his four-seamer. The pitch has added 1.6 inches of rise since last season, and that has made all of the difference. Batters have fouled off 29.7% of Gausman’s four-seamers this season. That’s 46 of them, the second-most of any pitch in baseball, behind Hunter Greene’s outstanding four-seamer. I watched all 46 of those fouls (and you can too if you’re messed up like me). The batters were underneath 45 of them, and late on most of them as well. (On the one foul where the batter wasn't underneath the pitch, they were just barely on top of it, and the pitch resulted in a foul tip into the catcher's mitt.) The uptick and velocity and rise is allowing the four-seamer to get on top of hitters, but as Lance Brozdowski noted on Friday, it's also about the location. Last season, Gausman attacked right-handed batters middle-up with the four-seamer, but this season, he's absolutely focused on jamming them high and inside with the pitch. It’s not enough to make them swing and miss, but enough to keep them from putting the ball in play, which lets Gausman get ahead in the count, which helps him keep runs off the board.

Similarly, his splitter isn’t getting as many whiffs as it used to, but you know what sits right between whiffing and putting the ball in play? That’s right, a foul. No offspeed pitch in baseball has earned as many fouls as the 20 Gausman’s splitter has earned. So Gausman is struggling with both whiffs and called strikes, but all those fouls mean that he's earning a strike (or a foul with two strikes) on 68.2% of his pitches, and that puts him in the 81st percentile. He's still throwing a whole lot of strikes.

The real question is whether Gausman can keep this up, and I am not at all certain. He’s is running a .143 BABIP right now, and there’s no way on earth that’s going to last. We should expect that number to double at least. He’s very definitely due for some regression, even if he manages to keep up all these foul balls. And I’m not sure he will keep earning all these fouls. Batters are more prepared than ever these days, with Trajekt pitching machines that mimic a pitcher’s exact offerings. They’re going to catch on about the increased vertical break and the up-and-in location and they'll train against it. At some point, they might not be swinging just under those pitches anymore. If they're not, look out. Baseball Prospectus’s Deserved Runs Allowed metric thinks that Gausman should be running a 5.77 ERA right now. It sees the lack of whiffs, the lack of strikeouts, and the good fortune on BABIP and home runs, and it thinks Gausman is due for some bad news. 

On the other hand, DRA doesn’t factor in Gausman’s raw stuff, and the advanced stuff models like Stuff+, StuffPro, TJStuff, and PitchingBot adore him right now. Stuff+ gives his four-seamer a 125 grade, putting it in the top 10 among starting pitchers. That really does give me hope me that this is sustainable, and he's combining that stuff with excellent command. Maybe he'll keep up all those fouls, or maybe he'll stop being so precise with the the location, or maybe some of them will start turning into strikes. I really don't know what's going to happen here. Gausman seems to be walking a very particular tightrope.

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