Freddie Steinmark was starting safety for the undefeated University of Texas Longhorns in 1969. In the thrilling “Game of the Century,” a come-from-behind victory against Arkansas that ensured Texas the National Championship, Steinmark played with pain in his left leg. Two days later, X-rays revealed a cancerous bone tumor so large that it seemed a miracle Steinmark could walk, let alone play football. Within a week of the Arkansas game, his leg was amputated.A gritty, undersized p...