Kevin Gausman Is Giving Batters Splitting Headaches

There are myriad reasons why the San Francisco Giants have been causing trouble in the NL West this season, crashing what was expected to be an exclusive party for the Padres and Dodgers. One of them is the starting rotation, which generally ranks in the top five in baseball whether you go by simple stats like ERA (third) and ERA- (fourth) or peripheral ones like FIP (second). Of the starting pitchers, none stands taller than Kevin Gausman, once a highly a touted Orioles prospect who has spent most of the last decade as a breakout candidate but hadn’t had that one big season. Wel, it appears he’s having it now.

At the top of the major-league leaderboards, there’s a lot of Gausman. Only Jacob deGrom has a better ERA among qualifiers, and that pitcher is having what could be a year for the ages. Gausman’s sixth in WAR, fifth in FIP, seventh in swinging strikes, and 10th in contact rate. And while he’s not likely to finish the year with an ERA anywhere near his current microscopic 1.27, his 2.20 FIP is an easy career-best so far and not explained entirely by the drop in league-wide offense.

So, what has changed for Gausman? The most obvious difference in the stats is the drop in home run total, a particular bugaboo for him at various points in his career. Playing in San Francisco instead of Baltimore has undoubtedly helped alleviate that concern, as has the decline in home runs in 2021, but just as with his overall FIP, it’s not just the environment. ZiPS’ peripheral home run estimator, zHR, sees his “true” home run rate as 2.1% of plate appearances, compared to his actual 1.7%. There’s been an interesting shift here; prior to 2020, ZiPS saw Gausman as the sixth-largest underperformer in terms of home runs allowed, allowing 130 homers where zHR expected to see only 108. Since joining the Giants, they’ve been a perfect match (13 homers vs. 13 zHR).

Nothing has drastically changed about Gausman. His exit velocities haven’t plummeted, he didn’t suddenly add 3 or 4 mph to his fastball, nor is there a new pitch in his repertoire. He’s still a pitcher who relies primarily on a mid-90s fastball and his fosh-esque splitter , a slower variant of the pitch that moves the splitter firmly in the camp of an off-speed pitch. (Orioles fans should be familiar with this offering because it was the bread-and-butter of Mike Boddicker in the ’80s.) There’s the occasional slider, a pitch that never really came into its own for Gausman and has been deemphasized in recent years, but he basically relies on the one-two punch.

Gausman’s fastball has been more effective than usual, but it’s the splitter that’s become otherworldly. We have pitch data going back to 2002, and Gausman’s splitter is already cracking the top 30 seasons:

Remember, this is isn’t a rate stat, but a counting one, so putting that together in just two months is mighty impressive. The pitch’s underlying characteristics haven’t really changed, but Gausman’s usage has, especially against right-handed batters. Without a truly effective breaking pitch but a fantastic splitter, Gausman’s had a reverse platoon split most of his career, with a .720 OPS against lefties and a .791 OPS against righties. Against righties, he didn’t have a true out pitch, with the splitter being the best with a .202 BA and a .369 SLG. For 2020-21, those figures stand at .071 and .118 respectively, with a swing-and-miss rate nearly 10 percentage points better than in the past (55% compared to 46%). Statcast sees a lot of that low BA being real; Gausman has an xBA of .104. And again, while the pitch itself hasn’t changed, the usage has. Before 2020, Gausman was throwing the splitter just over a fifth of the time when ahead against righties; since then, he’s doing so nearly half the time.

Also new? Where he’s throwing it. Not only is Gausman using the splitter in the counts that you’d expect to see a wicked breaking pitch — if he had one — he’s now also locating the splitter more like something with a sinister bend.

Gausman’s splitters have come lower and more towards the center of the plate against lefties as well, but it was always an amazing pitch against lefties. Now he has an out pitch against righties, one that allows him to have a pseudo-breaking ball that’s better than his actual one.

Naturally, this improvement by Gausman is also now reflected in the projections. ZiPS always had a soft spot for him, but the chances of him being a Cy Young contender had mostly faded.

Gausman’s improvement is enough to push up his projections by about a win a year since March, a notable shift for a veteran pitcher. It’s moved him from solidly above-average to a reasonable All-Star candidate in years he’s throwing 180 innings or so. I obviously don’t have full 2022 projections yet, but 3.7 WAR would have ranked Gausman 12th among pitchers in the preseason projections in 2021, up from his actual ranking of 41st. It also suggests a pitcher who should get a contract this offseason in the neighborhood of Zack Wheeler’s five-year, $118 million deal with the Phillies. He also will hit free agency unencumbered by a qualifying offer.

It’s probably too soon to start talking free agency; Gausman’s job right now is to help the Giants shock the NL West. And if he finishes with the 15-5, 2.80 ERA, 5.0 WAR season he’s currently projected to by our Depth Charts, the Giants may have some rare odd-year postseason magic in them.