Research regarding personality as predictors of objective physical performances has been limited and equivocal. We examined longitudinally whether personality predicted baseball pitchers’ (n = 119) or hitters’ (n = 115) performances after controlling for past performances. Through regression analyses, we determined that personality did not significantly predict the player’ performances during their first year in Minor League Baseball (MiLB). Our results indicate that, at least in the short-term, personality may be a poor predictor of such performances. Research is needed to determine if personality’s effects may occur over a longer period of time, such as through the development of psychological tools/strategies (e.g., motivation, coping) that are associated with improved performances.