With no more than 150 milliseconds to identify and assess an incoming pitch, Major League Baseball (MLB) hitters rely on exceptionally fast thinking to make near-instantaneous swing decisions. Consequently, players employ cognitive heuristics to quickly associate new information with existing mental references, introducing a vulnerability to behavioral biases. Using pitch-by-pitch data from MLB’s Statcast, we evaluate individual swing decisions under a behavioral economic framework, with a focus on prospect theory. Our findings corroborate the theorized presence of both the representativeness heuristic and loss aversion in player decision-making at the pitch level. First, we find that batters, after observing more than two consecutive similar pitch results (balls or strikes), are more likely to anticipate the same outcome on the following pitch. We also find convincing evidence of loss aversion, with players exhibiting pronounced asymmetries in risk preferences with respect to count context. Specifically, our analysis reveals that batters are significantly more risk-seeking in two-strike counts, and more risk-averse in even and 3-0 counts. This behavior is observed even when controlling for pitch characteristics and trade-offs in expected utility.