Pavlidis: What makes a good changeup?
From SABR member Harry Pavlidis at Baseball Prospectus on August 30, 2013:
If there was a noteworthy finding in the early stages, it was that pitchers who succeed at coaxing ground balls with their changeups generally looked dissimilar from those who missed bats with theirs. The pitchers who can do both are the best. Stephen Strasburg topped that list, so the first waft of the sniff test was passed.
The difference between a bat-misser and a worm-killer mostly boils down to firmness, for lack of a better term. Having some sink (pfx_z for you PITCHf/x folks) and tilt (the vertical angle of the ball as it crosses home plate) benefits pitchers near either pole of the changeup sphere. But it diverges from there.
A fastball with plus velocity and a sizable gap (10+ MPH) between the heater and the changeup make for more missed bats with the offs-/peed pitch, while a smaller gap helps the pitcher to induce more ground balls. Everyone needs tilt and/or sink, but guys who throw hard and can get separation on their fastball/changeup combo can try to miss bats. Those who don't have that gap and/or plus velocity are generally better suited to pitching to contact.
At least, that's what the numbers say about major-league pitchers. The guys who can miss bats know it, and use their changeup to put guys away in two-strike counts. The guys who can't miss bats also know it, and try to use their changeups earlier in the count. There is also a group that does neither; however, as shown in part one, those guys are self-aware and seem to avoid the pitch in general.
Does any of this mean anything in terms of player development?
Read the full article here: http://www.baseballprospectus.com/article.php?articleid=21675
This page was last updated August 30, 2013 at 1:14 pm MST.