Herb Score
As the 1955 American League Rookie of the Year, Score struck out 9.7 batters per nine innings, best in the majors, when the average pitcher struck out just 4.4 batters per nine innings. He was even more dominant the following season. But in 1957 he took a liner off the face, then a year later started dealing with elbow trouble, and the lefty was never the same again.