This study applied the generalized matching equation (GME) to pitch selection in MLB during the 2016 regular season. The GME was used to evaluate the pitch selection of 21 groups of pitchers as well as 144 individual pitchers. The GME described pitch selection well for four of the 21 pitching groups and 32 of the 144 individual pitchers. Of the remaining groups and individual pitchers, behavior may be explained by rule following behavior or be impacted by distant reinforcers such as salary. All 21 groups demonstrated a bias for fastballs as well as 119 of the 144 individual pitchers. The results extend the use of the GME to natural contexts and suggest an alternative view to evaluating pitchers. / Applied Behavioral Analysis