Gerrit Cole Has Made a Tweak

Despite playing for the Yankees and having the largest contract ever handed out to a pitcher, I think Gerrit Cole’s start to the 2021 season is going under the radar. Now, I have no empirical evidence that this is the case, but go with me here. I think two things are at play. First, Jacob deGrom is striking out every batter he faces (do not fact check me on that) and plays in the same city. Second, the Yankees’ struggles have been the talk of baseball in the early going, with much of the focus centered on the lineup and rightfully so. The team’s performance thus far has been extremely underwhelming, though they are 9-4 since their 5-10 start.

None of the blame for the Yankees tepid beginning can be put on Cole, however. He is off to a fantastic start. Through his first six starts, he has struck out 44.3% of the batters he has faced and walked only 2.1%. That strikeout rate is third in the majors behind deGrom and Corbin Burnes; the walk rate sits fourth in the league behind Burnes, Zach Eflin, and Walker Buehler. Put those two figures together and Cole has a K-BB% of 42.1%, only a few percentage points behind Burnes and deGrom and a shade under 10 percentage points above Joe Musgrove. The difference between Cole and Musgrove is about the same as the difference between Musgrove and Clayton Kershaw who is 19th on the leaderboard. Cole’s 2.4 WAR is tops in the league, though he has made one more start than both deGrom and Burnes, though I will note that he has only thrown two and two thirds more innings than deGrom so on a rate basis he has actually been more effective in accumulating WAR. Most of the difference has to do with a .315 BABIP allowed compared to deGrom’s .241 and a strand rate that is 8.3 percentage points lower.

So, Cole has been great. But this is not a breakout. Cole has been one of the best handful of pitchers in the sport since he first donned an Astros uniform in 2018. In the three preceding seasons, he posted a 36.6% strikeout rate and 6.8% walk rate over 485.2 innings, good for 6.05 WAR per 200 innings pitched. What is notable is that early on, he is pitching as well as ever. Better even. Since 2018, Cole only has one six start stretch where he struck out at least 44.3% of opposing hitters (44.6% from the end of July to end of August in 2018) and he has never posted a six start stretch walking so few batters (on a rate basis). At this point baseball fans are accustomed to Cole’s dominance over the opposition, but the degree to which he is doing so is unprecedented.

Cole’s pitch mix is largely unchanged, save for one notable exception. He has relied more heavily on his changeup than in any other season in his career:

Unsurprisingly the offering is saved for opposite-handed batters. The changeup is still his least-used pitch against right-handed hitters but when facing a platoon disadvantage, it is now the pitch he has turned to the second most-often, narrowly edging out his curveball (62 changeups versus 61 curveballs). He is using the changeup more against righties but the change is even starker against lefties:

I would say the change is for the best. After posting relatively neutral platoon splits in both seasons in Houston, Cole struggled (by his standards) against left-handed hitters in 2020. With the caveat that it is still very early in the season and outlier results are bound to regress, the pitch mix alteration has been effective:

Cole Performance by Batter Handedness
Season wOBA vs. L wOBA vs. R
2018 .241 .299
2019 .255 .261
2020 .322 .264
2021 .141 .249
SOURCE: Baseball Savant

His results last year against left-handed hitters necessitated some change. His three main offerings were not inducing swinging strikes at rates commensurate with a pitcher of Cole’s caliber. The changeup, on the other hand, was still able to yield swings and misses in spite of his struggles without the platoon advantage. Furthermore, the slider in particular was damaging when thrown to end plate appearances against left-handed batters in terms of wOBA allowed.

SwStr% by Pitch Type and Handedness
Season Batter Stands CH FF KC SL
2018 L 12.3 17.1 11.4 20.5
2018 R 13.3 10.5 13.4 17.0
2019 L 20.0 22.0 10.2 20.3
2019 R 12.7 10.9 11.7 21.3
2020 L 20 12.1 12.7 13.7
2020 R 0.0 9.9 21.0 25.1
2021 L 22.6 17.9 9.8 38.9
2021 R 23.3 6.8 8.5 23.3
SOURCE: Baseball Savant

wOBA Allowed by Pitch Type and Handedness
Season Batter Stands CH FF KC SL
2018 L .221 .244 .197 .291
2018 R .357 .307 .405 .245
2019 L .200 .244 .357 .238
2019 R .550 .288 .176 .228
2020 L .325 .322 .259 .375
2020 R 0 .316 .287 .191
2021 L .062 .096 .358 .160
2021 R 0 .339 .180 .223
SOURCE: Baseball Savant

Since 2019, Cole has been able to turn to the changeup to generate swings and misses against left-handed batters. The slider’s merits in this regard are not quite as strong. After consistently running swinging strike rates around 20% with the slider facing opposite-handed hitters, 2020 marked a stark decline. Now that Cole is more egalitarian with his pitch-mix against lefties, his slider has the best swinging strike rate in the last four seasons. It’s a similar story when you look at overall results. Lefties tattooed his slider to the tune of a .375 wOBA in 2020 after not finding much success in 2018-19. With Cole’s pitch mix transformation, it is now back to a viable pitch. The changeup, in terms of wOBA, continues to be his best offering against lefties, as it has since he arrived in Houston.

Using the slider less against lefties and the changeup more has led to career-high whiff rates on both pitches and has powered his uptick in strikeouts:

He has used the pitch to effectively generate whiffs against left-handed hitters on the outer edge of the plate while he continues to be able to generate swinging strikes by working the same areas of the plate against right-handers:

The approach to left-handers has yielded a much higher whiff rate on the outside portion of the plate. This is an intuitive result given the success of the changeup because a right-hander’s changeup fades away from a left-handed hitter, so pitches low and away have the best chance of missing barrels.

Cole is not going to continue to allow a mere .141 wOBA against left-handed hitters. His .249 figure against right-handers is also bound to regress. But after allowing a wOBA almost 80 points higher when the batter had the platoon advantage in 2020 compared to ’18-19, it is encouraging to see him make a substantial adjustment. Cole has a history of making major adjustments to his repertoire. Upon arriving to Houston, he scrapped his two-seamer and began throwing more breaking balls and almost immediately became one of the best pitchers in baseball. To see him continue to tinker on the margins should be encouraging for both the Yankees and the club’s fans alike. Cole was still very good in 2020, with much of the downtick in production compared to ’18 and ’19 due to the ball flying out of the ballpark at an unsustainable rate. With this new adjustment in tow, it will be worth watching to see how close he can get to his heights in Houston.





Carmen is a part-time contributor to FanGraphs. An engineer by education and trade, he spends too much of his free time thinking about baseball.

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tomerafan
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tomerafan

And that adjustment is not pitching to Gary Sanchez.
🙂

johndarc
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johndarc

Except he was great on Opening Day pitching to Gary, and actually credited Gary for calling for the changeup when he didn’t have command of his slider.

tomerafan
Member
tomerafan

Respectfully, I think Cole was being kind to his catcher in the aftermath of that game rather than throw him under the bus, which I appreciate. They did not look in sync at all, and Cole looked frustrated by the calls Sanchez was making, even if his face-saving explanation was that he was frustrated with himself rather than his catcher. But I’ve seen Cole upset with himself, and this didn’t look like that. YMMV.

lewisletterman
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lewisletterman

This reads like someone who was told something by the people involved, but refuses to believe and only accepts their truth. Even if you are a passive observer with no inside knowledge and have no insight.

tomerafan
Member
tomerafan

Or someone who watches way too much baseball, and that’s it.

(Sure, players always tell the truth about what they’re feeling, especially when a reporter is trying to get a pitcher to throw their catcher under the bus. And sure, the in-game announcers DURING THE GAME pointed out multiple times the frustration that Cole was expressing and that it looked like he was more frustrated with Sanchez than himself. But yeah, sure, I only “accept my truth,” whatever that means. And people wonder why independent, critical thinking is dying, dying, dying…)

symanski2021
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symanski2021

Who are these “people” that are wondering “why independent, critical thinking is dying, dying, dying”? Sounds like you may need a new circle of people.

DirtyHec
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Member
DirtyHec

LMAO

hughduffy
Member
hughduffy

Gerrit Cole pitching to:
Gary Sanchez: 9 G, 51.1 IP, 3.86 ERA, .226/.284/.482 BA/OBP/SLG allowed
Kyle Higashioka: 9 G, 59.1 IP, 1.06 ERA, .158/.184/.225 BA/OBP/SLG allowed

Cole and Higashioka really do get on the same page.