Random relievers can do loopy issues in small samples. Who can ever neglect Nationals right-hander Justin Miller placing out 57.9% of the hitters he confronted throughout a three-week stretch of 2018? Or Kody Funderburk’s legendary whiff explosion to shut out the 2023 Twins season? Guardians reliever Hunter Gaddis is on one in all these incendiary strikeout runs, and it’s driving me to insanity.
Gaddis may not strike you as working on the similar degree of random as Miller and Funderburk. By any set of affordable requirements, Gaddis broke out final season, showing in almost half of his group’s video games whereas delivering a 1.59 ERA. However — forgive me — I didn’t actually purchase it. His 23.7% strikeout price matched the league common for relievers, and his arsenal didn’t precisely justify a .205 BABIP. Given his pitch shapes and peripherals, I figured Gaddis would settle in as extra of a strong middle-relief sort than one of many premier backend arms within the league. After which this April occurred.
He’s solely pitched 13 1/3 innings throughout 15 appearances this season, nevertheless it’s onerous to pretend a 37.5% strikeout price, even in a pattern of simply 56 batters confronted. That’s good for tenth amongst all pitchers with a minimal of 10 innings pitched. Other than Justin Lawrence, who was mercifully unshackled from excessive altitude, no one has come near displaying this form of strikeout improve.
Naturally, the follow-up query goes one thing like: What’s he doing in another way? Certainly he’s added a brand new pitch, or gained a bunch of velocity, or dropped his launch level, proper? Mistaken, truly. None of these items are true. Gaddis hasn’t added a elaborate new pitch. He isn’t throwing means more durable. (He’s truly misplaced a little bit of fastball velocity.) So what’s the deal? Why is he Mason Miller all the sudden?
My first thought: It’s bought one thing to do along with his slider. He threw that pitch 45% of the time in 2024, and the explanation why is fairly clear: It’s an 89.6-mph slider. The typical main league slider travels 4 mph slower. Under are all of the sliders thrown in 2025 grouped by pitcher. Gaddis’s falls within the bucket on the outer proper fringe of the histogram:
In 2025, his utilization price on his slider all the way in which as much as 60%; solely Orion Kerkering throws his slider extra incessantly. As pitchers across the league development towards diversifying their pitch combine, Gaddis is zigging, throwing his favourite pitch like his profession is determined by it.
It’s not simply the utilization that’s modified. Gaddis subtly altered his mechanics over the offseason, climbing his arm angle up three levels whereas extending a pair additional inches down the mound. Consequently, his pitches are transferring in another way. His fastball gained 1.5 inches of experience, whereas his slider gained almost three inches.
Normally, extra experience on sharp sliders is undesirable. The thought is to have as a lot vertical separation between the fastball and slider as doable; the extra the slider strikes like a fastball, the extra possible it’s to be hit. Stuff+ downgraded Gaddis’ slider from a 97 to a 91 this season; PitchingBot is much more pessimistic, taking it down from a 41 to a 33.
So, in accordance with the stuff fashions, Gaddis made his slider worse. He’s additionally throwing it greater than ever. One way or the other, he’s almost doubled his strikeout price. As the youngsters say, the mathematics ain’t mathing.
One risk is that the fashions don’t actually know what to make of Gaddis’ slider form. At almost seven inches of induced vertical break and 5 inches of glove-side motion, his slider exists in form of a slider/cutter no man’s land. (A slutter, if you’ll.) There aren’t actually that many pitches that match the motion profile of the Gaddis slider. The closest comparability I might discover is Kyle Leahy’s slider, which he throws simply as onerous with comparable extension and motion. Leahy is off to an excellent begin, however the whiff charges on his slider hover round league common. Similar with the cutters of Ryan Johnson and Mitch Spence, two pitches that resemble Gaddis’ slider from a motion perspective.
However there’s a giant distinction within the targets of those respective pitches. Leahy, possible because of the velo and form, tends to throw his slider up within the zone. It’s returned nice run worth, however that’s largely because of the batted ball high quality and fewer concerning the whiff price. Johnson and Spence additionally elevate their cutters and see comparable patterns of whiff versus contact suppression.
In 2024, Gaddis’ slider places tended to be concentrated center away to righties. That’s modified in 2025. Have a look at the heatmap of slider places to right-handed batters in 2024:
And now in 2025:
Gaddis is repeatedly concentrating on low and away to righties, concentrating his sliders within the places most primed for whiffs.
To left-handed hitters, the swing-and-miss location is similar. Gaddis needs to throw it glove facet to the hitter’s again foot, hoping for swings like this one which Brooks Baldwin delivered on an 0-0 rely in early April:
The situation fashions are muted on Gaddis’ command expertise. Each BotCMD and Location+ suppose his slider places are inside a degree or two of the league common. I whipped up a primary model of the Kirby Index for sliders, measuring the usual deviation of vertical and horizontal places for all sliders thrown to right-handed hitters and grouping by every particular person pitcher. Gaddis’ location density ranks within the seventieth percentile for pitches labeled as sliders, a bit higher than the fashions, however nothing that implies a Jacob deGrom-level command of the pitch.
He additionally mixes in his Bugs Bunny changeup to each righties and lefties. It strikes on roughly the identical trajectory as his fastball however travels about 16 mph slower than the heater; the result’s some really loopy swings. It’s onerous to make Alex Bregman look this foolish:
That mentioned, his changeup command is just not nice, which prevents Gaddis from counting on the pitch as a lot as he may like.
I’ll have to return clear right here and say that I’m not precisely positive what to make of Gaddis’ efficiency thus far. The stuff fashions suppose his stuff is anyplace from mediocre to unhealthy. He has no prior monitor document of lacking bats at anyplace close to this degree. And his places are higher than they had been final 12 months however they’re not something particular. So far as I can inform, this run appears fueled by Gaddis’ throwing an uncommon pitch to fairly good places. Typically, it looks like there must be a transparent smoking gun for a efficiency shift of this magnitude. However typically it’s the buildup of some small modifications, blended in with a sprinkle of that traditional baseball randomness. I suppose I’ll need to reside with that.