How Jameson Taillon’s Cutter Became Unhittable

[Davy Andrews]

In 2023, Jameson Taillon's cutter graded out as his second-worst pitch. In 2024, that same cutter graded out as the fourth-best cutter in all of baseball. What happened to it? Like, seriously, what the hell happened to it?

Image courtesy of © Chet Strange-Imagn Images

Jameson Taillon’s Baseball Savant page is a mess. Savant rates pitchers by their run values, and Taillon’s run values are all over the place. At the very top, his fastball run value is listed at 19 runs, which puts him in the 98^th percentile. That’s incredible!

But if you look at the individual pitches, you’ll see that his four-seam fastball, the pitch he throws more than any other, was worth exactly zero runs this season, and his sinker was worth four runs. That huge fastball total is coming almost entirely from his cutter, which was worth 15 runs, making it the fourth-most valuable cutter in all of baseball.

Last year, though, the same pitch was worth -5 runs, and the year before that, it was worth 0 runs. In 2019, Taillon’s sinker was his best pitch by run value. It was his four-seamer in 2021, his curveball in 2022, his sweeper in 2023, and now his cutter in 2024. If you can make any sense out of the graph below, either you’re a whole lot smarter than I am or you’re imagining things.

Like I said, it’s a mess. Based on run values, the only thing we can say for certain is that Taillon’s changeup has always been bad. He added the cutter to his repertoire in 2021, and it was mostly a middling pitch until this year, when it magically turned into Cutter King Kong. How did it suddenly become a great pitch, and will it ever climb the Empire State Building?

Let’s start by breaking down what run values are, and why Baseball Savant uses them. At first, it might seem logical to examine a pitch based on an overall metric like wOBA. The problem is that only the last pitch of a plate appearance affects wOBA. A single will always have a wOBA of .882, and strike three will always have a wOBA of .000, but strike one and ball one don’t affect wOBA at all, so you’d be ignoring a huge number of pitches. Run value is calculated by taking the difference between the expected run state before and after each pitch. For example, if the pitcher throws a strike on the first pitch of the inning, the number of runs you’d expect the offense to score in that inning goes down by 0.033. Therefore, that pitch is credited with gaining 0.033 runs for the pitcher. If you the pitcher throws strike one with nobody on and one out, then they only get credited with 0.023 runs, because the extra out meant that the offense was starting with a lower expected run state. It’s not a perfect system, but it allows you to count every pitch.

Okay, so back to our original question: How did Taillon’s cutter accrue so much value in 2024? I’m going to start by knocking off a few of the usual suspects. Here’s a list of things that didn’t happen to his cutter in 2024:

• It didn’t gain a bunch of velocity.
  • Its velocity fell by more than two full ticks, from 88.6 mph to 86.5.
• It didn’t earn more chases.
  • Its chase rate cratered, going from 34% to 24%.
• It didn’t earn more whiffs.
  • Its whiff rate cratered too, falling from 27% to 19%.
• It didn’t start inducing more soft contact.
  • Its exit velocity and hard-hit rate both went up.
• It didn’t start inducing a bunch more groundballs.
  • Its groundball rate fell from 41% to 38%.
• It didn’t start inducing more popups.
  • Its popup rate fell from 10% to 7.5%.

So, uh, that’s a whole lot of reasons that you’d normally expect a pitch to succeed, and exactly none of them happened. That said, there were some positive changes. 

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[Brock Beauchamp]

Outstanding work, Davy. Whew, that was quite a read, so much to process.