Spin rate is how fast a pitched ball rotates, measured in revolutions per minute, or rpm. More spin on a fastball makes it resist gravity and appear to rise, while more spin on a curveball adds break. The average four seam fastball in the majors spins at roughly 2,300 rpm, and every pitch in the game is tracked by Statcast.
Why Spin Matters
| Pitch | High spin effect | Low spin effect |
|---|---|---|
| Four seam fastball | Rides and gets swings and misses up in the zone | Sinks more, induces grounders |
| Curveball | Sharper, bigger break | Loopier, easier to read |
| Changeup | Less fade | More drop and fade, the goal |
Spin Isn’t Everything
Raw rpm matters less than how the spin is used. Spin that moves the ball, called active or useful spin, creates movement, while gyro spin, like a bullet spiral, does not. That is why two pitchers with the same rpm can throw very different pitches. Grip enhancers that raised spin rates led MLB to crack down on foreign substances in 2021, with umpires checking pitchers during games.
Related
Exit velocity · Launch angle · What is a sweeper
Pitch tracking definitions from Baseball Savant.