Earlier this week, Baseball Savant unveiled their new pitch movement data. We’ve had access to pitch movement since PITCHf/x data became publicly available in 2007. That’s been useful for comparing a pitcher to himself, but it hasn’t quite been effective at comparing pitchers to each other. For one, the data hasn’t been kept in one place. Brooks Baseball doesn’t have leaderboards. For another, not all pitches are created equal. The Savant data should make it easier for us to the rest of the league. Theoretically.
The numbers are a little confusing, so I’ll do my best to explain copy and paste Mike Petriello’s explanation.