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Jon Gray’s slider is helping him through lost velocity

Shoulder issues have impacted Jon Gray’s velocity, but a drop in velocity may be helping his slider.

Arizona Diamondbacks v Colorado Rockies Photo by Justin Edmonds/Getty Images

Like so many of us, Jon Gray undoubtedly wanted to leave 2020 behind. The shortened season was the righty’s worst by just about every metric. His strikeout rate got cut in half to 12.6 percent. His ERA nearly doubled to 6.69. His FIP was a career-worst 5.06. The only thing that went right was that he posted his lowest walk rate of his career, but hitters didn’t really need to be patient as Gray also induced his worst hard-hit rates and xwOBA of 46.0 percent and .361 respectively.

The struggles in 2020 were mostly the result of shoulder issues, but Gray’s performance has always been mercurial. One year, he looks like a down-ballot Cy Young candidate and the next he’s getting optioned to Triple-A. Just the year before it all went wrong, Gray arguably had his best year. In 2019, he put up a 3.86 ERA, 4.06 FIP, and 3.97 DRA across 150 innings. By RA9-WAR, he was worth 4.0 wins, easily his best mark. Two years prior, he was a bit better at preventing runs, but didn’t have the workload.

Gray, then, has a pattern of everything coming together every other year, and if he was bad last year, then he should be good this year, right?

So far, yes. He’s been stellar. By bWAR, Gray is tied with Mike Trout for sixth-most valuable player in the majors. In two starts, Gray has struck out 12 batters in 11 23 innings while only allowing two runs. He’s walked five, which is the lone blemish, but he hasn’t surrendered a long ball yet. What’s more is that he’s done all this at Coors Field and one of those starts was against the Dodgers.

That point about being tied with Mike Trout in WAR should reveal that it’s too early for any of this to matter. Until Trout is at the top of the WAR leaderboard, it’s still small sample szn. Still, it’s worth investigating whether Gray is doing anything differently, and perhaps the fact that someone actually took the time to write an article about Jon Gray spoils the answer, but yes, he is.

In fact, he’s doubling down on changes he made last season despite the disastrous results. Gray has always had four pitches in his arsenal (five if count his seldom-thrown sinker). Mostly, he’s relied on the fastball and slider while mixing in a curveball. Occasionally, he would throw a changeup, but from 2017-19, he threw it less than three percent of the time.

In 2020, Gray altered his pitch mix. He began using the changeup far more frequently while the curve took a back seat. Gray also threw the lowest percentage of fastballs in any previous season which might have been a response to him losing velocity on the four-seamer.

Baseball Savant

In 2021, it’s been more of the same: even fewer fastballs and curveballs and even more changeups and thus far, a career-high percentage of sliders thrown.

It’s interesting that Gray stuck with the changeup because it was arguably the cause of his woes last year. By Baseball Savant’s Run Value, Gray’s changeup was the third-worst in MLB last year. The changeup only induced a 23.7 percent whiff rate, a fairly paltry amount for an offspeed pitch. When hitters did connect, they obliterated it. Hitters combined for a .625 xwOBA against the pitch, making it the most-punished changeup in the majors.

Gray has stuck with the changeup this season, but the jury’s still out on whether it’s a good pitch. It hasn’t been clobbered, but it also hasn’t been swung on and missed yet. The changeup isn’t playing more than a supporting role in Gray’s ensemble. The leading role belongs to his slider.

Throughout his career, the slide piece has been Gray’s best swing and miss pitch, and that’s continued into 2021. So far, Gray’s slider has induced a 48.5 percent whiff rate, which, if it holds, would be the best mark of any pitch he’s thrown in any season. This early success has come in spite—or because of—a drop in velocity.

Before 2020, Gray averaged no lower than 87.5 mph on his slider and it was 88.3 mph in 2019. Last year, Gray averaged 86.3 mph on his slider and it’s down to 85.6 this year. Gray has dealt with shoulder problems in recent years and those have prevented him from hitting 96 with his fastball. Velo is supposed to be paramount, but this drop in velo has been accompanied by more actual drop.

Baseball Savant

On average, Gray’s slider is dropping two inches more than it was the year before and the year before, it was dropping two inches more than the year before that. Again, Gray has only pitched at Coors this year where breaking balls don’t break as much. Slower pitches will generally drop more (there’s more time for gravity to pull on the pitch), but this isn’t just a result of not throwing as hard.

Since 2019, Gray has added around 150 rpm of spin to his slider (and only his slider, so don’t call the foreign substance police) and that has likely contributed to his extra movement.

Baseball Savant

This is more or less the same formula that saw Jon Gray have his worst season, but it’s working two starts into 2021. It’ll be interesting to see how well Gray’s changeup performs as the season goes on, and if the increased movement on the slider offsets a slight drop in velocity. Gray is a free agent at the end of the year, and with how inconsistent his career has been, he needs to enter the market on a high note.


Kenny Kelly is the managing editor of Beyond the Box Score.