Parnell spent his entire 10-year career with the Boston Red Sox (1947-1956) and compiled a 123-75 record with 732 strikeouts, a 3.50 earned run average, 113 complete games, 20 shutouts, and 1752.2 innings pitched in 289 games (232 as a starter). He is the third best ever lefty pitcher in Fenway Park with more than 25 decisions at 71-30 .703. Parnell enjoyed his best season in 1949 when he went 25-7 leading the league in wins, ERA (2.77), complete games (27) and innings (295.1). He was the starting pitcher for the American League in that's year All-Star Game and was selected again in 1951.