Pitching glossary
What the numbers mean
Every pitching metric, explained in plain language, with what’s average, good, great, and excellent.
Velocity
How fast the ball travels, in mph. Usually the peak speed just after it leaves the hand.
What is pitch velocity? Spin · rpmSpin rate
How many times the ball rotates per minute after release, measured in rpm.
What is spin rate? Spin · rpmActive spin
The part of total spin that moves the ball. The rest is gyro spin.
What is active spin? Spin · %Spin efficiency
The percent of total spin that creates movement. 100 percent means no gyro spin.
What is spin efficiency? SpinSpin axis
The direction a pitch spins, shown as a clock face. It sets which way the ball moves.
What is spin axis? Spin · °Gyro degree
How far the spin axis turns toward home plate, from 0° (all useful spin) to 90° (pure bullet spin).
What is gyro degree in pitching? Movement · inInduced vertical break (IVB)
How many inches spin moves a pitch up or down, measured against a spinless ball.
What is induced vertical break? Movement · inHorizontal break (HB)
How many inches spin moves a pitch sideways, toward the arm side or the glove side.
What is horizontal break in pitching? Pitch qualityStuff+
A model score that grades a pitch's velocity, spin, and movement, where 100 is league average.
What is Stuff+ in baseball? LocationPitch location
Where a pitch crosses home plate, which shows whether it was a strike and how well it was commanded.
What is pitch location, and how is it measured?No terms match that search.
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