Heilmann's batting average in 1921 was 85 points higher than his 1920 average and 101 points higher than his career average prior to 1921. Some attributed Heilmann's dramatic improvement to the tutelage of Ty Cobb, who took over as the Tigers' manager in 1921. Others attributed Heilmann's improvement to the "live-ball era" that started in 1920 and forced outfielders to spread out and play deeper, allowing more of Heilmann's line drives to fall into the wider gaps. However, Frank G. Menke attributed his improvement to having learned the game, noting that the "lively ball" failed to account for the fact that those who outhit Heilmann from 1914 to 1920 were no longer outhitting him. Menke observed: