The Relationship Between Pitch Location Scatter Plots and Arm Slot
During the last offseason, I was looking at a scatter plot of Cleveland pitcher Tanner Bibee’s pitch locations, and it reminded me of a regression line with a negative slope. I had a similar thought after watching Aaron Nola’s knuckle curve location. However, the slope of Nola’s regression line is more gradual than Bibee’s. While this may be the result of various factors—such as the trajectory and usage of breaking balls, as well as command—I focused on something a little different: arm slot. Nola’s average arm slot is 20 degrees, whereas Bibee’s is 51 degrees. And arm slot does have some correlation with pitch movement. I looked into the relationship between pitch location scatter plots and arm slots. Here’s how: • I plotted pitch location scatter plots for pitchers who threw more than 100 pitches of each pitch type. • From these scatter plots, I drew regression lines and calculated the location correlation coefficients for each pitcher. • Then, I compared the corr...