Herbert Orin "Fritz" Crisler was an American college football coach who is best known as "the father of two-platoon football," an innovation in which separate units of players were used for offense and defense. Crisler developed two-platoon football while serving as head coach at the University of Michigan from 1938 to 1947. He also coached at the University of Minnesota (1930โ1931) and Princeton University (1932โ1937). Before coaching, he played football at the University of Chicago under Amos Alonzo Stagg, who nicknamed him Fritz after violinist Fritz Kreisler.