 He started the 1941 season in the minor leagues with the Buffalo Bisons, then was brought up midseason, making a big impression, batting .345 with a .400 on-base percentage and a .509 slugging percentage.In just 54 games, Mullin had 76 hits, scored 42 runs, with 21 extra base hits.Based on his performance in 1941, Mullin appeared to be a rising star.