Kershaw is doing something incredible for his age.
Clayton Kershaw has always been excellent.
Every year from 2011 through 2016, Kershaw ranked in the top-three of pitcher fWAR, including first-place fWAR finishes in 2013 (7.2), 2014 (7.9) and 2015 (8.6), as well as a tie for first with the late José Fernández in 2016 (6.3). Over that six-year stretch, Kershaw produced a total of 43.4 fWAR, the highest mark among any pitcher by nearly a 13-win margin. (Max Scherzer ranked second during that span, with 30.5 fWAR.) Kershaw has been one of the most dominant pitchers in baseball history, and the accolades have piled up: eight All-Star appearances, three Cy Young awards and the 2014 NL MVP.
From 2017 to 2019, Kershaw remained incredibly effective, but signs of age began to show. His on-field numbers were still quite good, though not nearly as dominant as during his peak: A 2.69 ERA, 3.38 FIP and 3.18 xFIP were all marks of a top-flight pitcher, but all steps below his 2.06 ERA, 2.26 FIP and 2.60 xFIP produced during the peak years. It wasn’t really fair for us as observers to consider Kershaw as on the downswing, since he still did rank 16th in fWAR over those three years, but the performance was clearly not the same. When you’re the best in the game, being “only” excellent starts to look like a decline, fair or not.
There were other reasons to think that Kershaw’s best days were behind him. Back issues have plagued him in recent years, requiring time on the Injured List in 2016, 2017 and 2018. He missed his Opening Day start with back stiffness this season as well. With that, Kershaw has experienced decreased fastball velocity. After averaging 93.6 mph on the pitch as recently as 2016, Kershaw was down as low as 90.3 mph last year, driving him to reinvent himself and rely more heavily on the off-speed. Early in his career, Kershaw threw his four-seamer more than 70 percent of the time. Last year, he threw it just 44 percent of the time.
Kershaw’s recalibration worked well, but working with diminished fastball velocity left him with less margin for error. He allowed 1.41 home runs per nine last year, the worst mark of his career, even after adjusting for run environment. His in-zone fastball results became noticeably worse:
This also meant that Kershaw could no longer challenge hitters in the strike zone. He nibbled more often:
In 2019, Kershaw was working more around the plate with the fastball than at any point over that five-year span. He still threw it in the zone more than 50 percent of the time, but he made an effort to decrease how often it bled into the heart. The strategy made sense, considering Kershaw’s fastball was now more hittable and less effective overall. His weighted pitch runs above-average with the four-seamer took a real tumble as well:
But then Kershaw went to Driveline. And though, in Pedro Moura’s words, Kershaw was “reticent to discuss” his experience, there’s been an obvious change in the results: He’s throwing the ball harder in 2020, even at the age of 32.
“They’re smart in how the body works, and how to create the most efficiency with your body, and how to create the most power with your body,” Kershaw told Moura in February. “They have ways to apply that. I think you can glean different things from different usages of it. Some guys are going in there maybe because there’s more in there and they’re trying to figure it out. Some guys maybe lost it.”
Kershaw’s average fastball velocity is not back to where it was during his peak, but he’s added 1.2 mph of extra oomph, jumping from an average of 90.3 mph in 2019 to 91.5 mph so far in 2020.
To underscore just how impressive it is for a 32-year-old pitcher to add that much velocity back to his fastball, consider this: From 2016 to 2019, a total of 97 pitchers who featured a four-seam fastball threw at least 30 innings in their age-31 and age-32 seasons. Just two of them added at least 1 mph of fastball velocity in their age-32 season.
64 of these 97 pitchers — or roughly two-thirds — experienced some sort of year-over-year velocity decrease from their age-31 to age-32 seasons. 45 of the 97, or almost half (!), experienced a velocity decrease of at least 0.5 mph. And 22, or almost a quarter, saw their fastball velocity decrease by at least 1 mph. On the flip side, just 27 pitchers saw any positive change, and only two experienced a positive velocity change of at least 1 mph, just as Kershaw has done so far this season.
But average fastball velocity only tells us so much. Kershaw has not only added 1.2 mph on average, but he’s also thrown eight pitches at or above 93.0 mph, after not reaching that mark once last year. His maximum fastball velocity in 2020 is 93.6 mph. In 2019, it was 92.6 mph. Here is the distribution:
Kershaw’s fastball is clearly being thrown harder. The average will tell you that, but the distribution is much more telling — we can visualize the difference here.
Despite the increase in velocity, the results on the pitch have been mixed. Hitters are whiffing at Kershaw’s four-seamer much more often — his 22.2% whiff-per-swing rate is his highest since 2015 — but they are also hitting it hard when making contact. He’s allowed just a .212 batting average and a .317 wOBA against it so far, but the .292 expected batting average and .415 expected wOBA could be cause for concern.
That’s not to say the added velocity hasn’t made him better. It has. The results are there so far: a 1.50 ERA, 3.26 FIP and 2.60 xFIP in 36 innings. Kershaw’s strikeout rate is back over 30 percent, walk rate back under 5 percent. The results we’ve seen in 2020 look quite similar to the Kershaw of the mid-2010s.
Pitching is interdependent. Better stuff on your fastball can make your other pitches play up. And, for Kershaw, they have. His slider and curveball look better than ever. It’s impossible to say whether the improvements there are just the result of the added velocity, or if he refined his off-speed stuff at Driveline as well. The velocities on all of his pitches are up — that could certainly be part of it.
What I can say, though, is that Kershaw is doing something rare. He took his decline and turned it on its head. A 32-year-old pitcher adding over 1 mph of fastball velocity: Clayton Kershaw continues to reinvent himself, proving yet again why greatness is a combination of both talent and adjustments.
Devan Fink is a sophomore at Dartmouth College and a Contributor at Beyond The Box Score. Previous work of his can be found at FanGraphs and his own personal blog, Cover Those Bases. You can follow him on Twitter @DevanFink.
