Jacob deGrom has ditched his sinker and minimized his curveball

Last Saturday night Jacob deGrom turned in a stellar performance against the Dodgers, one of the best hitting teams in the league. He pitched seven shutout innings while striking out eight batters, walking no one, and allowing only three hits. He was a big part of the Mets’ 3-0 victory, a victory that they really needed if they want any chance at getting that last Wild Card slot, a possible, though not probable endeavor (the team is sitting several games back with only a most chance of taking the second NL wildcard per FanGraphs).

deGrom is continuing his stellar Cy Young performance from last year. A 1.99 RA9 is incredibly difficult to duplicate no matter how good you are, but a 2.79 RA9 is still excellent, and his 31.6 K% and 5.7 BB% are almost identical to his rates from last year.

The biggest difference for him has come from the juiced balls. He gave up only 10 home runs all of last year, but he has already given up 19 this year. It should be noted, however, that his home run rate and HR/FB ratio this season are more in line with his career rates. Last year was the outlier, which should not be surprising in a season where a pitcher allowed so few runs.

Things were not looking so good for deGrom in April. He had a 4.85 RA9 at the end of the month and was just not looking like his old self. Unsurprisingly, it was a small sample size aberration. He has had a 2.47 RA9 ever since, and now he is currently in the Cy Young race. It once looked like Max Scherzer was the clear front runner to win this fourth Cy Young award, but he has missed some time due to injuries. I won’t do a complete breakdown on how those two compare here, suffice it to say that I do not envy NL Cy Young voters this season.

I watched the Mets/Dodgers game on Saturday night through MLB.tv (I know the game was nationally televised, and even without knowing who was calling the game on ESPN, this Mets fan decided to go with the team’s home broadcast). At one point, SNY aired a previously recorded short interview with Mets interim pitching coach, Phil Regan. He was discussing a bullpen session with deGrom when he asked him if had just thrown a sinker. deGrom replied saying that he does not throw sinkers anymore, and that the previous pitch was a fourseamer that he was adept at keeping down.

Sinkers are no longer in vogue in today’s game, as discussed here in detail by FanGraphs’ Ben Clemens. The Astros, for example, are well known for getting their pitchers to ditch them. As much as I would like to say that deGrom’s change in repertoire was the result of sound analysis from the front offices that expertly communicated to him, there was no way that was going to be the case because this is the Mets we are talking about.

deGrom came to this decision on his own. As much as this numbers guy would love to tell you that analytics were the driving choice behind his decision making, that does not appear to be the case. It was still logical, though, just more qualitative than quantitative. He concluded that with the launch angle revolution of recent years, it did not make sense to throw a pitch that has movement that would complement swings that have more upper trajectories.

Fourseamers have less movement than sinkers, but that, according to deGrom, was where the advantage lies. Of course, fourseamers do not rise because it is impossible to impart enough spin on the ball to counteract gravity, but they can be perceived as rising to a hitter who is expecting the fastball to drop some. deGrom’s rationale, one that is backed up by work done by the Astros, Rays, and other progressive teams, is that hitters will tend to swing under these pitches.

Brooks Baseball

As you can see above, this change started last year, the year he became one of the best pitchers in baseball. He started throwing his slider more and his fourseamer less in 2017, and then increased usage of his fourseamer while dropping the use of his sinker precipitously. He used his sinker about 17 percent of the time in 2017, and then used it less than 10 percent of the time last season. This year he barely ever uses it. His usage of it is only at half of one percent. He has thrown a total of just 15 sinkers all year according to Brooks Baseball.

they didn’t discuss curveball usage in that interview with Regan, but as you can see from the graph above, deGrom’s usage of that has dropped, too, albeit not as drastically as his sinker. He threw the curve about 11 percent of the time in 2016, and has used it less and less since then. It is down to about three percent usage now, as he has thrown fewer than a 100 curveballs all season. One has to wonder if his reasoning behind that is the same as with his sinker. Curveballs, of course, have a more pronounced downward movement, though at substantially lower velocities than sinkers.

As deGrom’s sinker and curveball usage were dropping, his slider usage has risen. It was at about 18.5 percent in 2016 and slowly rose to 24 percent last year. Now it shot up to nearly a third of his pitches thrown. His fourseamer is also seeing the highest usage rate of his career at nearly half the pitches he throws. His changeup has become his main third pitch, one that he throws much more often to lefties for obvious reasons.

He is not 2018 deGrom, but 2019 deGrom is still a true ace and still one of the best pitchers in baseball. He is on the wrong side of thirty, but he at least he has been able to stay healthy since 2017. If he keeps showing this ability to adjust, he should remain effective for a while to come.

. . .

Luis Torres is a Featured Writer at Beyond the Box Score. He is a medicinal chemist by day, baseball analyst by night. You can follow him on Twitter at @Chemtorres21.

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