Article: Kevin Gausman’s 2024 Decline Might Be Fixable: A Healthy 2025 Could Restore His Dominance

[Jesse Burrill]

The advanced numbers show why Gausman may not have been 100% in 2024, and what he might need to do to get back there in 2025.

From 2021 through 2023, Kevin Gausman was one of the best pitchers in baseball. Over that period, his 15.5 fWAR were tied for the second-most among all pitchers, and among starters with at least 200 innings pitched, his FIP and xFIP both put him in the top five. He finished in the top 10 in the American League Cy Young, voting in all three seasons. A large part of that success came because Gausman had one of the best weapons in baseball, his nasty splitter. Splitter usage across baseball has risen over the last few seasons, leading to articles about the Splitter Revolution and the Year of the Splitter. The numbers speak for themselves.

The increased splitter usage shouldn't come as a surprise. In an MLB.com article, Mike Petriello used the table below to break down the trend. It shows that on a per-pitch basis, the splitter increased its value more than any other pitch type.

Gausman’s splitter was one of the best. He threw it 37.1% of the time over those three years, with Stuff+ marks of of 112, 119, and 105. But in 2024, it was a different story. The pitch's Stuff+ fell to just 88, and it wasn’t nearly as good as generating whiffs either. From 2021 to 2023, Guasman's splitter ran a 44.6% whiff rate. In 2024, it fell to 32.4%, the lowest mark of his career. Part of the reason for the drop-off was that the pitch broke less. The pitch lost more than an inch of arm-side run and more than two inches of induced vertical break. It also saw its velocity increase by nearly a full mile per hour, even though Gausman's four-seam fastball actually declined in velocity. In other words, there was less of a gap between the two speeds, so the splitter represented less of a change of pace from the fastball.

There could be many reasons for the decline of Gausman's splitter. He's going into his age-34 season and he’s thrown at least 180 innings in each of the last four seasons. It's possible that he's tipping his pitches again. All of those could be true, but I have another theory that may give some hope he may bounce back in 2025. Kevin Gausman was never fully healthy in 2024.

At first glance, that might seem ridiculous. Gausman made 31 starts last season, throwing 181 innings without missing a start, but two things can be true at once. You can be healthy enough to pitch but not healthy enough to be at your best, and I’d argue Gausman never got to his best. Flashback to spring training 2024: Gausman got into camp and said he “tried to do too much too early,” and ultimately, the Blue Jays shut him down for most of Spring training with right shoulder fatigue. He got into the last game of spring before making his season debut on March 31. Gausman later told Sportsnet that starting the season on the IL might have been best for him.

You never want to see right shoulder fatigue, especially from a guy who has thrown as many innings as Gausman. A decline in arm angle is one possible indicator of a shoulder injury. The shoulder muscles, particularly the rotator cuff, are crucial for maintaining proper arm position during throwing. When injured, these muscles may not provide enough stability, leading the humerus (upper arm bone) to rotate internally more than desired, causing the arm to drop. There is a history of this, too. CC Sabathia, one of the newest members of the Hall of Fame, saw his arm slot drop in 2010 and eventually dealt with a meniscus tear that season. Gausman's arm angle has slowly dropped throughout the few seasons.

Not only that, but Gausman's has dropped steadily as the season within the last couple seasons. The graph below shows the month-by-month breakdown.

There is likely more to it than this, Gausman might have just been tipping his pitchers. His arm angle on his splitter last year was 34 degrees, whereas when he threw his fastball it was 37 degrees. That may not seem like much, but when you’re predominantly a two-pitch pitcher like Gausman is, major league hitters can likely pick up on this small difference. This could be why we saw him incorporate more sliders and sinkers as he got deeper into the season.

The hope here is that with an offseason full of rest, Gausman can get fully past the shoulder injury. If the arm angle can rise yet again and he can get that “bite” back on his splitter, Gausman has a chance to bounce back to the high-end starter that he was prior to 2024. Its a big ask, but for a Blue Jays team with playoff aspirations, a healthy and effective Kevin Gausman will go a long way to getting this team to the promised land.

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[Laika]

Damn 

Probably a hamburger meat shoulder 

[Eat My Shatkins]

Watch, 2025 will feature a huge bounce back from the pen, an offense that's actually half decent, but the rotation will just crater the season into oblivion.

[Spanky99]

33 minutes ago, Eat My Shatkins said:

Watch, 2025 will feature a huge bounce back from the pen, an offense that's actually half decent, but the rotation will just crater the season into oblivion.

'Tis baseball... 😅

Great article... Jesse.

[Stangstag]

2 hours ago, Eat My Shatkins said:

Watch, 2025 will feature a huge bounce back from the pen, an offense that's actually half decent, but the rotation will just crater the season into oblivion.

Thats Bluejays baseball 

[FellerFromFortune]

He's a starter that only throws 2 pitches, hitters have him figured out. 

[Brownie19]

15 minutes ago, FellerFromFortune said:

He's a starter that only throws 2 pitches, hitters have him figured out. 

After 12 years in the majors, hitters finally noticed he only had 2 pitches 😂

[BatFlip]

Jesus, he might be a submarine pitcher by the time his contract is over.

Great article! 

[FellerFromFortune]

13 hours ago, Brownie19 said:

After 12 years in the majors, hitters finally noticed he only had 2 pitches 😂

Well he's moved around a fair bit and he hasn't had 12 good season that is for sure. 

[Brownie19]

3 hours ago, FellerFromFortune said:

Well he's moved around a fair bit and he hasn't had 12 good season that is for sure. 

I'll take "things that don't make sense for $200 Alex"

[FellerFromFortune]

On 1/26/2025 at 11:48 AM, Brownie19 said:

I'll take "things that don't make sense for $200 Alex"

Well when you play in different leagues you face hitters you typically haven't faced. If you look at Kevin Gausman's performance after he's in the same league for a few years his performance drops. It happened in Baltimore and now it's happening in Toronto.