Recent research has shown Major League Baseball (MLB) players that bat left-handed and throw right-handed (i.e., sinister right-handers), have a higher batting average (BA) in comparison to players with other combinations of batting and throwing handedness. Possibly owing to early exposure to hockey, Canadian-born MLB players have an increased propensity to be sinister right-handers, however, it has yet to be determined whether this provides a relative offensive performance advantage compared to players born in other countries. Using the largest archival dataset of MLB statistics available, the present study examined whether being Canadian-born influences offensive performance indirectly through handedness. Offensive performance measures included: BA, slugging percentage, on-base plus slugging percentage, on-base plus slugging percentage plus, homeruns, runs batted in and wins above replacement. Findings revealed that since the inception of MLB, left-handed batters (regardless of throwing hand dominance) demonstrate the best offensive performance across each metric. The relative proportion of Canadian-born sinister right-handers is at least two times greater than players from other regions, although being Canadian-born does not provide a direct offensive advantage. Using Iacobucci's (2012) extension for computing mediation involving categorical and continuous variables, results showed evidence of a significant indirect effect in that being Canadian-born increases the odds of being a sinister right-hander and in turn leads to greater performance across each offensive performance metric. Collectively, findings provide further support for Cairney and colleagues (2018) hockey influence on batting hypothesis and suggest this effect extends to offensive performance.