Tommy Kahnle has the best changeup in baseball

What’s your favorite kind of pitch? There’s something to admire in Aroldis Chapman or Jordan Hicks blowing a 103 mph heater right by a hitter. Adam Ottavino has certainly won over a lot of Yankee fans with his hilarious, frisbee-like slider. For me though, there are few things sweeter than a really, really well-placed changeup that makes a batter swing right over top.

Felix Hernandez and Marco Estrada are two good examples of pitchers I watched growing up who would dominate major league lineups with a changeup that, even when you knew it was coming, hitters would struggle to no end with. The Yankees have a pitcher like this too, and his name is Tommy Kahnle.

After an inconsistent and injury-riddled 2018, Kanhle has roared back with a stellar 2019, turning into as important a piece as any in the Yankee Bullpen of Doom. This has become even more important for the team as it’s grappled with the loss of Dellin Betances all year. The secret to Kahnle’s success in 2019? That changeup.

Now usually a pitcher will work a changeup off his fastball - throw 97 over the plate to get ahead, and then the 89 mph offspeed down to get a strikeout. Kahnle doesn’t do that, using his changeup for more than half his pitches, despite it having less of a velo difference than conventional wisdom would say he should have:

His changeup averages about 6.5 mph less than his fastball, which is actually below the MLB median of 7.4 mph. The velocity difference in and of itself isn’t particularly exceptional, so why does he throw it so often?

First, he has remarkable command over the offspeed stuff. In successive relief outings, look what he does with the changeup to two right-handed hitters:

He can locate the pitch to the outer corner down, or inside and up, and get pretty messy whiffs on both pitches. That’s not really something most pitchers can do, and that gets reflected in his FanGraphs’ pitch value:

Pitch values are essentially the runs generated off a particular pitch, relative to your peers. Kahnle’s changeup is as valuable as any in baseball, and he throws it so often that we have a better idea of its value compared to a pitcher only throwing it 15% of the time.

In fact, if you take the set of pitchers who have a higher changeup value than Kanhle:

Only Luis Castillo, in the midst of his breakout year for the Reds, comes close to Kahnle in terms of whiffs.

Kahnle’s use of the changeup is yet another analytical success of the Yankees. The team has made it a policy to focus on your best pitch, and let the rest of the game happen as it may. The idea of having a balanced repertoire, or working off the fastball, just doesn’t really fly with this organization. To wit, Kahnle was traded to the Yankees throwing his changeup 20% of the time. Last year that rocketed up to 40%, and this year it’s half.

Understanding your strength and basing your approach around that is sort of the core of modern baseball analytics, and Kahnle’s no different. He has the best changeup in baseball, he uses it a lot - and could even be justified in using it more! - and it’s going to be a lot of fun to keep seeing all those ugly whiffs.