Pick a pitcher, choose an anchor pitch type, and click anywhere in or around the strike zone. The anchor pitch lands at your click point. Each other pitch in the arsenal appears at the position it would arrive if aimed at the same initial point, based on movement differentials — showing you how the arsenal separates from a shared start. Drag any bubble to move the entire arsenal.
Bubble size reflects each pitch’'s actual movement spread. Switch modes in settings to show each pitch's location represented by one baseball width.
Navigate forward to interact with the calendar and select a date. Press the question mark key to get the keyboard shortcuts for changing dates.
Navigate backward to interact with the calendar and select a date. Press the question mark key to get the keyboard shortcuts for changing dates.
Movement differentials are calculated by assuming that pitches are aimed such that their spin-less, gravity-less flight would end in the same location at home plate. They capture how spin and speed alter the trajectory of a given pitch in flight. They also serve as a rough guide to “what the batter saw”. If you mistake one pitch for the other, you might expect the ball to end up at the fastball’s location, only to see it end up where the slider does instead.
Separation lines display the straight-line distance between paired pitches aimed at the same point. All distances are calculated relative to the chosen anchor pitch and displayed in inches.
Vertical Approach Angle (VAA) depends on pitch characteristics as well as plate location. It is dynamically recalculated based on each pitch’s location as you drag the arsenal around. The higher the plate location, the less negative the VAA, and vice versa. Research shows that pitches with extreme approach angles, particularly relative to similar pitches thrown to the same location, are associated with better results for the pitcher.
Bubble sizes are calculated by taking the standard deviation of each pitch’s movement, both horizontally and vertically. A larger bubble means larger variation in movement for the same pitch type. Optionally, baseball mode displays each pitch as the diameter of a baseball.
Pitchers sometimes, but not always, pair their pitches in this manner. They might pair some of their pitches but not others. This tool is best used as an understanding of what a pitcher could do, not as a complete listing of all the ways their pitches relate to each other.
Data shown is season averages from the batter’s perspective.
