Changing It Up: Determining the Nash Equilibria for Major League Baseball Pitchers

In order to prevent batters from hitting a pitch, pitchers must decide on a strategic balance of many different pitch types. While each pitcher has preferred pitches (likely those with which he is most confident), he cannot over-utilize his dominant pitches, or batters will be able to gain a strategic advantage in trying to put the ball into play. We analyze Major League Baseball (MLB) pitch data from 2008 to 2018 in order to determine whether or not MLB pitchers are able to reach the theorized mixed-strategy Nash equilibrium given the pitcher’s skill in utilizing each type of pitch. Our data suggests that MLB pitchers are in fact rational, and succeed in reaching the mixed-strategy Nash Equilibrium.