The More Tommy Kahnle Changes, The More He Changes

They say everything in baseball happens in cycles. Actually, I’m not sure if they say that, but it certainly sounds like a real quote. And that’s fortunate for me, because today I’d like to talk about another thing that happens in cycles: Tommy Kahnle being a valuable reliever. Years after it seemed like that might never happen again, he’s back on the Yankees and pitching well, to the tune of a 2.66 ERA and 3.97 FIP across 40.2 innings of work, that despite a four-walk disaster of an outing on Wednesday night.

The last time Kahnle was good and healthy was also with the Yankees, in 2019. Before that, you’d have to go back to 2017 (split between the White Sox and Yankees). He was hurt and ineffective in 2018, then only pitched a combined 13.2 innings from 2020 to ’22 due to injury. But now here he is, back at it, though you might not know it thanks to the Yankees’ general desultoriness (probably not a word, but my spellcheck didn’t flag it, so let’s roll with it).

Maybe you’re thinking that Kahnle’s semi-resurgence isn’t worth an article. Plenty of relievers put up good ERAs across 40–50-inning spans. But here’s my counter-argument: we write articles about a lot of players and teams here. Plenty of things are article-worthy. And I’m less interested in Kahnle’s success than how he’s doing it. Here, for your perusal, is a list of the pitchers who throw changeups most frequently:

Kahnle is so far out in front. No one else pitches like this. And you can understand why no one else pitches like this intuitively – They call it a changeup for a reason. Kahnle is spinning the changeup-heaviest season in the pitch tracking era, or in other words, since we’ve taken the time to classify which pitch a pitcher is throwing.

Kahnle didn’t always pitch like this, though he’s always had an excellent offspeed offering. This change (thank you, thank you, I’ll be here all week) in pitch usage has been building up more or less continually since he hit the majors:

Last year, Kahnle only pitched 12.2 innings, so he didn’t hit the minimum in my “changeup-iest seasons of all time” search. But it doesn’t take a rocket scientist to see a pattern here. Every year, Kahnle decides he likes his changeup a little more and his fastball a little less. Every year, he acts on those preferences. It’s nice to see a plan in action.

But what a weird plan. We talk about pitchers leaning more on their best pitches all the time, but that usually means breaking balls with outrageous movement, or occasionally splitters that disappear into thin air. Kahnle’s changeup doesn’t quite fit that bill; it has less fade than average, and he throws it so hard that it has slightly positive vertical movement after stripping out the effects of gravity. It doesn’t get a ton of horizontal movement either. Nor does he get a ton of seam-shifted wake on it or throw it from a wild arm slot. Nothing jumps out to me in my first look at its raw measurables.

But as it turns out, there’s a lot to like about the pitch that isn’t immediately obvious. First, he throws it hard — 88.8 mph on average. That makes for a small gap between fastball and changeup, but more importantly it gives hitters less time to react than to an average changeup. When this thing is coming your way, you’ll have to recognize offspeed fast to be able to do anything about it.

Second, even though it has upward movement relative to spinless flight, that’s true of pretty much every changeup thrown that dang hard. Fifty-five pitchers have recorded higher average changeup velocities than Kahnle this year, which is shocking in and of itself, but only five of those pitchers induce less upward movement. It’s genuinely hard to kill as much lift as he does, even from his low arm slot. That means that major league hitters have spent a long time looking at changeups that hardly resemble Kahnle’s offering.

Here’s another way of looking at it: Kahnle throws his changeup about as hard as Kyle Freeland throws his sinker. Kahnle’s changeup falls 32.3 inches on its path home; Freeland’s sinker falls only 27.7 inches. It’s really hard to produce that kind of drop throwing the ball nearly 90 mph.

If you watch the pitch, you might start to understand:

It’s an optical illusion. From the delivery and velocity, it feels like it should stay in the zone, and it just doesn’t.

Kahnle can manipulate that fade when he needs to as well. Against dangerous hitters and in advantageous spots, sometimes the pitch just vanishes completely:

You’d think that hitters would catch on and start sitting on changeup. Honestly, they have. He’s posting a swinging-strike rate well below his career mark on the pitch. The thing is, it’s still 16.8%, an excellent number. You can do the math pretty easily from that. Let’s say he didn’t get a single swing and miss on a fastball all year. His overall swing-and-miss rate would be three-quarters of 16.8, because he throws three-quarters changeups. That’s 12.6%. Pitchers across the majors have compiled an 11.1% swinging-strike rate this year.

Because of that extreme downward movement, Kahnle also gets a ton of grounders on the pitch. So if you’re keeping score at home, his changeup induces a boatload of grounders and also misses a ton of bats, even when he uses it almost all the time. It’s also fairly immune to platoon splits, naturally enough; it’s a changeup. Why would he want to throw more fastballs, exactly?

The answer to that is that his fastball functions like a regular pitcher’s secondary option. He throws a four-seamer so rarely that opposing hitters struggle to catch up to it. It’s a wholly unremarkable pitch, to be honest; decent velocity (95.3 mph) but average vertical and horizontal movement. Relievers who rely on fastballs like that generally get tattooed in this era of power. Stuff+ gives his fastball a 94; PitchingBot’s stuff grade is a 47 on the 20–80 scale. But his 10.5% swinging-strike rate on that pitch is better than league average anyway, because batters are heading up to the plate thinking changeup and then flailing ineffectually when Kahnle changes it up with a heater.

Will this keep working? I don’t know! It feels really weird, and it’s completely without historical precedent. Surely, batters are going to catch on. Kahnle’s changeup is drawing fewer chases than ever, and it’s not the kind of pitch that I’d be excited to live in the strike zone with. It all feels very unstable, like a gust of wind could turn Kahnle into a pumpkin, to mix metaphors just a bit.

Still, that hasn’t happened yet, unless Wednesday night is a harbinger of more to come. Kahnle is delightfully weird and effective, a breath of fresh air in a Yankees season that has mostly been a dour march towards 85 losses. If you find yourself watching some of their games down the stretch, my condolences, but also check out an endearingly fun middle reliever who’s doing something novel in complete obscurity.