Changeups Are Weird

Below are two changeups. Can you tell which one is better?
First up is Griffin Jax’s power changeup. He throws it over 92 mph; at two inches of induced vertical break (IVB) and 15 inches of arm-side run, it almost resembles a filthy left-handed slider:
Second is Hunter Gaddis straight change, floating up to the plate with 10 inches of IVB at an average velocity of 78 mph:
So, which one would you take? That’s a bit of a trick question: By whiff rate, these two pitches are virtually identical. Jax’s changeup ranks second in all of baseball with a 57.3% whiff rate; Gaddis’ is right behind him in third. Stylistically, they’re opposites; by the results, they are indistinguishable.
If you were creating the perfect fastball or the perfect slider in a video game, it’d be a straightforward process. Crank up the velocity, max out the vertical break, and those pitches will generally improve in a roughly linear fashion. Not so with changeups. Pitch models struggle to accurately grade these pitches because their quality can’t as easily be captured by velocity and movement in a vacuum. The Cole Ragans changeup, for example, gets a roughly average grade by Stuff+ despite performing like the best changeup in the sport over the last handful of seasons. It’s slow, and it barely moves — what makes it so good?
Thanks to new data from Baseball Savant, I think the answer might soon be clear. Read the rest of this entry »






