With nearly half the season behind them, the Giants have shown that their early success was no fluke; they possess the best record in baseball and the best run differential in the National League. Much of their success can be attributed to their starting rotation, which ranks fifth best in the majors in park- and league-adjusted FIP and ERA. Those are some incredible results considering most of that rotation was built with bounce-back candidates.
Kevin Gausman is the headliner on San Francisco’s staff, and if it weren’t for Jacob deGrom’s historic season, he’d be the front-runner for the NL Cy Young award. But his success was pretty easy to predict after his 2020 campaign. The real surprise this year has been Anthony DeSclafani.
DeSclafani has shown plenty of promise in years past. During his first three years in the major leagues, he compiled 5.3 WAR and a 3.99 ERA backed by a 3.78 FIP. But the strong start to his career was cut short by an oblique injury that cost him nearly half of the 2016 season, then a strained UCL kept him off the field for all of ‘17. He managed to avoid Tommy John surgery, but struggled upon returning from his elbow injury the following year. Things really fell apart in 2020. He started the season on the IL with a strained back muscle, was eventually demoted to the bullpen by the end of September, and was left off the Reds’ playoff roster for their first-round matchup against the Braves, ending the year with a 7.22 ERA and 6.10 FIP.
Short on suitors, DeSclafani signed a one-year, $6 million contract with the Giants in the offseason — one that has paid off handsomely for both player and team. He’s posted career-bests in ERA and FIP and is on pace to accumulate nearly 4 WAR this year, and outside of a 10-run disaster against the Dodgers on May 23, he hasn’t allowed more than three runs in any of his starts and just six total since then.
The changes DeSclafani has made to his repertoire and approach are many, so let’s start simple: his pitch mix.
His slider has always been his best weapon, and he’s throwing it more than a third of the time in 2021 — the second highest rate for that pitch in his career. He’s also upped the usage of his changeup this year, with both increases coming at the expense of his four-seam fastball.
Since returning from his elbow surgery in 2018, his slider has been a work-in-progress; the speed and the shape have deviated wildly over the last four years.
Anthony DeSclafani, Slider Physical Characteristics
| Year |
Velocity |
V Mov |
H Mov |
Spin Rate |
| 2018 |
86.8 |
33.9 |
4.4 |
2231 |
| 2019 |
89.4 |
27.4 |
3.7 |
2315 |
| 2020 |
86.1 |
38.2 |
4.2 |
2218 |
| 2021 |
87.4 |
32.2 |
4.5 |
2195 |
The only thing that’s stayed consistent through the seasons is the horizontal movement. In 2019, it looks like DeSclafani attempted to add velocity to the slider at the cost of some vertical movement. Last season, that velocity dropped back down to its previous level, but he was able to add more drop. This year, he’s found a healthy middle-ground; the velocity is higher than it was in 2018 and ‘20, and the vertical movement is right around where it was four years ago.
So how have these changes affected the slider’s results?
Anthony DeSclafani, Slider Results
| Year |
Whiff% |
CSW% |
GB% |
xwOBAcon |
| 2018 |
36.9% |
28.9% |
43.3% |
0.376 |
| 2019 |
29.3% |
27.4% |
43.7% |
0.353 |
| 2020 |
34.8% |
24.4% |
40.4% |
0.409 |
| 2021 |
32.9% |
28.6% |
48.1% |
0.348 |
Despite all these evolutions, the slider has remained very effective. In 2019, when he added all that velocity, it actually saw its lowest whiff rate of the last few years. The next year, more vertical movement resulted in the lowest groundball rate out of the last four seasons. In 2021’s happy medium, his whiff rate has dipped a bit, but he’s inducing a lot more contact on the ground to offset the loss of those swings and misses.
DeSclafani’s changeup has also undergone some significant changes this year. That was a pitch he was committed to working on this spring, and that tinkering has had some interesting effects. He’s added more than an inch of arm side run to the pitch, but batters aren’t really swinging and missing against it, with a mere 9.2% whiff rate (surprisingly not a career low). Instead, he’s using the pitch to generate tons of weak contact. He throws his changeup almost exclusively to left-handed batters, and when hitters put it in play, they’re running a .299 xwOBA.
DeSclafani locates his changeup in the zone around 45% of the time, which matches what he was doing in 2018 and ‘19. But last year, that zone rate was just 28.6%, while its whiff rate was the highest it’s been over the last four seasons. That might just be a coincidence; he threw just 42 changeups last year after all, and the zone rate on all of his pitches was down. That loss of command was a big reason why his walk rate ballooned to 10.1%. This season, he’s gotten back to locating in the zone more often, and his walk rate has fallen back down to his career norms.
The best thing about all those additional strikes is that DeSclafani’s contact rate has continued its downward trend. It’s still a touch above average, which puts a cap on his strikeout ceiling, but he’s earning more called strikes and avoiding free passes again, and when batters do make contact, they’re not doing much damage. His groundball rate is the highest it’s ever been, and his massive home field advantage has helped him push his home run rate to well below league average.
With a long injury history to worry about and just one season with more than 180 innings under his belt, DeSclafani’s stamina could become an issue for the Giants down the road. For now, though, he’s settled in as the second-best starter in a very good rotation in San Francisco and has found the best version of himself after all that tinkering.
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Jay Jaffe