Bullpen Focus

The purpose of this session was to focus on the ‘Dodger Slider’. The idea was made popular by this article from The Athletic by Eno Sarris. The article talked about inferred vs observed spin direction from Hawkeye, and how seam shifted wake (SSW) could play a role in the difference between inferred and observed.

During this bullpen, both Rapsodo and Trackman were used. For the purpose of this report, we will only breakdown the Trackman Data.

All pitch types were thrown during this session. “Slider” was my own traditional slider grip, while “Other” was the slider grip used by Blake Treinen.

Spin Efficiency uses an estimation model based on Dr. Alan Nathan’s work.
NOTE: Trackman struggles with low spin pitches such as Knuckleballs and Splitters, so some data may not be available for those pitch types.

Bullpen Summary

Below are the averages for each pitch type thrown.

Pitch by Pitch Table

Below is a list of each pitch thrown during the bullpen.

Plots

Below are plots made from the data. All plots are interactive aside from the Radar plot; aka “Spin Efficiency vs Spin Direciton”