Tucker was named the American League Player of the Month on Monday, and O'Neill took National League Player of the Month honors.
O'Neill's breakout 2021 season helped carry the Cardinals to a 17-game winning streak in September and an NL Wild Card berth. The 26-year-old left fielder batted .328/.377/.731 with 13 home runs, 30 RBIs, 31 runs scored and an 1.108 OPS in September and October.
O'Neill led the National League in home runs, RBIs, runs scored and slugging percentage for that period, and was also the Major League leader or co-leader in all those categories.