Tommy Kahnle’s Changeup is Unhittable

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Tommy Kahnle has been dominant in 2019. He is pitching to a 2.73 ERA (3.17 FIP) in 52.2 innings with 77 strikeouts (37.2%) and just 16 walks (7.2%). If you remove his disastrous London Series outing–can we just all agree to get rid of those stats at this point?–his numbers would look even better. (“Remove the times he was bad” is a time-tested baseball analysis trick, but I think the London Series is a unique case.) But even still, he’s been absolutely dominant.

It is obvious to anyone who has watched Tommy Kahnle pitch this season that he is utilizing a mesmerizing changeup. I mean, just look at this thing:

I could honestly watch that all day. It is so, so beautiful. Anyway, I noticed that Kahnle is throwing the change much more this year and decided to look into it a bit. Check it out:

That’s a very noticeable adjustment right there. He threw his change a ton in 2015, dropped off in 2016, and has been building it back since joining the Yankees in 2017. He’s now using the pitch about 50% of the time in 2019, which is a career high by a significant amount. That’s not all, though. He’s also using it more on a month-by-month basis this year. Look at this:

That is a very steady, month-by-month increase. In April, he threw changeups 32% of the time. In August, he’s done so over 62% of the time, an increase of just about 100%. He’s all but abandoned his slider, cut back on his fastball, and really deployed his changeup as a weapon. A tweak that significant is pretty clearly intentional, and I think that change is a huge reason why Kahnle has returned to his 2017 playoff form.

Check out how batters are faring against the pitch in 2019:

  • Batting Average: .112 (.131 xBA)
  • wOBA: .154 (.172 xwOBA)
  • Slugging Percentage: .187 (.206 xSLG)
  • Average Exit Velocity: 85.3 mph
  • Whiff-Per-Swing Rate: 49.80%
  • Grounder Rate: 62.50%

So, yeah. I think it’s pretty clear as to why Kahnle is throwing it more: that is one of the finest pitches in baseball right there. Peel back the layers a bit further, though, and there are even more encouraging signs.

You know how Kahnle has been using that changeup more? Well, the increased usage hasn’t impacted its effectiveness at all. Let’s look at some of those same figures again, this time only for the month of August:

  • Batting Average: .105 (.124 xBA)
  • wOBA: .135 (.161 xwOBA)
  • Slugging Percentage: .140 (.183 xSLG)
  • Average Exit Velocity: 85.7 mph
  • Whiff-Per-Swing Rate: 45.28%
  • Grounder Rate: 60.00%

Good grief are those some pretty numbers, huh? The usage has increased significantly and the effectiveness hasn’t really changed at all. If anything, it’s gotten *more* effective, but the sample size is small enough that we can’t really say for sure. What we can say for sure, though, is that Tommy Kahnle’s changeup is a hell of a pitch. And he basically dares batters to swing at it. Look at his heatmap:

He’s putting it right there and mostly keeping it in the zone. That’s a “swing, I dare you” type approach. Most hitters have dared, but few have been rewarded–he’s allowed just 12 hits in 105 chances on the pitch, with just 4 of those registering for extra-bases (2 HR).

Kahnle’s success in 2019 has been a major breath of fresh air for the Yankees, and it’s really extended the Yankee bullpen in a significant way. Underneath much of that success is a changeup that’s truly unhittable–and a new approach, for which both the Yankees and Kahnle deserve credit. I leave you with this work of art:


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  1. I hope he doesn’t start getting lit up after you wrote this. ;-)>

  2. Wire Fan

    Kahnle is also a good reason why the Yankees don’t need another lefty bullpen arm. That change plays up against lefties.

    He is essentially a match-up lefty when they need it. He has a 43% K rate against lefties this year vs 32% against righties, and also has a lower wOBA allowed facing lefties

    He is a great complementary piece to Ottavino who can have trouble with lefties.

  3. dasit

    style guide request:

    when writing about kahnle, cahn you add an unnecessary h before every n?

    don’t bahn me for this (sandwich joke)

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