Kevin jairaj-emin photographs
Within the introduction to their 2023 Saberseminar presentation, Scott Powers and Vicente Iglesias hit on a elementary reality about pitching: The variable that bests predicts the end result of a pitch is the situation the place it crosses the plate. For a case research, look no additional than this tweet from MLB.com’s David Adler about Yoshinobu Yamamoto’s splitters.
Hitters have swung 74 occasions at Yoshinobu Yamamoto’s splitter this season …
38 of these swings are whiffs (51%)
One other 17 are foul balls
That leaves 19 balls in play
18 of these 19 are floor balls (95%)
Just one of Yamamoto’s splitters has been hit within the air pic.twitter.com/ggLR1qHYZW
– David Adler (@_dadler) April 22, 2025
If Yamamoto buries his splitter arm facet, he’s most likely getting a whiff. If it’s on the sting of the zone, it’s doubtless a foul ball. If it catches plate, it’s getting put in play. The placement dictates the end result.
Given this reality, pitchers who command the ball finest should dominate. However there’s a catch. As Powers and Iglesias famous, the situation can be the variable with the least predictive reliability. For those who see a pitcher throw a fastball 98 mph, you will be fairly certain he’s going to do it once more. A dotted backdoor slider, then again, doesn’t assure a whole sport of dotted backdoor sliders. Command is each crucial and the least dependable high quality for a pitcher.
Scott Powers and Vicente Iglesias, 2023 Saberseminar
No person can nail the corners with each pitch. However pitchers can no less than decrease the variance of their places, discovering relative reliability throughout the chaos of command. And in 2025, there may be maybe no person extra dependable than Jacob deGrom.
deGrom’s flat assault angle fastball and agency slider have (justifiably) constructed his popularity as a stuff monster. Even after easing up on the fuel pedal this season, deGrom continues to be a darling within the eyes of the fashions. His total Stuff+ is within the eightieth percentile for starters with no less than 30 innings pitched, fueled by his depth-y 89-mph slider. PitchingBot likes deGrom much more, rating him within the prime 10 amongst these pitchers. Over at Baseball Prospectus, the StuffPro mannequin believes deGrom wields 4 pitches — his curveball and changeup, along with the heater and slider — that each one grade out as plus.
However stuff is not deGrom’s carrying software. Probably as a operate of his determination to throw slowerprobably as a constructive consequence of growing olderdeGrom’s standout talent nowadays is his command.
deGrom’s unbelievable precision got here to my consideration whereas writing about Hunter Gaddis for a chunk that was printed on Monday. As a part of my effort to discern whether or not Gaddis owed his early-season success to slider command (the decision: inconclusive), I created a model of the Kirby Index for sliders to see the place he landed. That metric measured the variance in launch angles and launch factors and distilled these figures right into a single rating that captured command means. Initially, it was designed for fastballs, which are usually thrown to all elements of the strike zone. It maybe works even higher for sliders, which usually are thrown to fewer targets. Gaddis’ rank amongst his fellow pitchers was nothing outstanding, however deGrom’s title sitting on the very prime caught my consideration.
Kirby Index (Sliders)
SOURCE: Baseball Savant
Minimal 50 sliders thrown to right-handed hitters.
As I wrote earlier this yr, a extra simple implementation of the Kirby Index can be to only measure the variance of the particular pitch places. For this story, I calculated the usual deviation of the vertical and horizontal places of a given pitcher’s sliders; as soon as once more, deGrom discovered himself on the prime of the pack. Take a look at how a lot distance there may be between him and the subsequent closest pitcher:
Location Variation (sliders)
Participant Identify
Horizontal Location (St Dev)
Vertical Location (St Dev)
General (St Dev)
Jacob deGrom
0.525
0.498
0.724
Merrill Kelly
0.595
0.586
0.835
Zac Gallen
0.616
0.565
0.836
Corbin Burnes
0.556
0.671
0.871
Jack Flaherty
0.575
0.659
0.874
Bryce Elder
0.514
0.713
0.879
Zack Littell
0.574
0.719
0.920
Luarbert Arias
0.543
0.755
0.930
ENYEL DE LOS SANTOS
0.732
0.619
0.959
Dylan Lee
0.493
0.827
0.962
SOURCE: Baseball Savant
Minimal 50 sliders thrown to right-handed hitters.
Random tangent right here, however you need to admire Luarbert Arias for refusing to throw his junky 82-mph slider anyplace however contained in the strike zone.
Anyway, measuring location densities, finally, might simply level at pitchers who replenish the strike zone; the true take a look at of command is a pitcher’s means to hit his precise goal. To that finish, Driveline Baseball supplied me with a pattern of their proprietary miss distance knowledge. Utilizing Inside Edge monitoring knowledge, Driveline measures the gap from the supposed goal to the precise location of the pitch.
No shock — deGrom’s slider miss distance ranked first amongst all pitchers. The league-average miss distance for sliders is about 12.5 inches; this yr, deGrom is lacking his goal by beneath 9 inches, almost three customary deviations beneath the common. Any approach you slice it, deGrom is commanding his slider like nobody else within the sport.
The outcomes have been unassailable. Thus far, deGrom’s slider has returned a run worth of -3.2 per 100 pitches thrown, the perfect mark for any slider thrown by a beginning pitcher. Not solely is he getting a bunch of swing and miss — a 38.1% whiff price, as of this writing — it’s additionally grabbing a ton of referred to as strikes. When batters do handle to place it in play, they will’t do a lot with it. The typical launch angle on the pitch is simply 2°; the xwOBA is a meek .227.
The innocent outcomes on balls in play are a operate of deGrom’s targets. To right-handed hitters, he targets the traditional low-away nook, breaking off the plate. Notice the bimodal distribution on the heatmap — there’s a big focus of sliders he’ll throw within the zone for strikes, after which one other cluster proper beneath the zone that generate chase.
These intentions will be seen within the filtered heatmap clusters. When deGrom throws sliders to righties in zero-strike counts, he tends to be within the zone:
In two-strike counts, he chases the swing and miss:
To lefties, deGrom exhibits an analogous bimodal distribution, however the sample seems reversed. In early counts, he’s aiming just under the zone; in late counts, he’s on the lookout for referred to as strikes. This sequence to Athletics rookie Nick Kurtzwhich featured 4 sliders, offers a way of the method. On 1-0 and 2-0, deGrom tries to bait a chase, however the large lefty resists.
Down 3-0, deGrom fires a middle-middle heater in an auto-take state of affairs, then returns to the slider in a 3-1 depend. Right here, deGrom dials in his robotic precision, dotting the decrease fringe of the strike zone to deliver the depend full.
On 3-2, he goes there once more. Kurtz takes it and pays the worth. Although the superimposed strike zone on the published says this pitch is simply low, my sense is he deserves that decision; if he’s persistently touchdown pitches inside inches of his supposed goal, you type of simply have at hand it to him.
deGrom isn’t simply portray with the slider. I calculated the Kirby Index for four-seam fastballs thrown to righties in 2025; extremely, he additionally sits in first place on that listing.
Kirby Index (Fastballs)
SOURCE: Baseball Savant
Minimal 50 fastballs thrown to right-handed hitters.
As good as it might be to assume that deGrom will be simply pretty much as good even after dropping two ticks off the fastball, it simply isn’t true. Absent enchancment elsewhere, shedding stuff will deliver him again to Earth. However deGrom is way from stagnant. In 2019 — his final full large league season, amid probably the most dominant part of his profession — his fastball command measured as beneath common by miss distance. Six years later, it’s exhausting to argue his command is something however 80-grade. And so long as the elbow cooperates, it’s going to assist him defy gravity.
