Rivera, 43, posted a 2.11 ERA with 44 saves in his farewell campaign. He struck out 7.6 batters per nine innings and walked only 1.3, which was one of the best single-season marks of his career.
The 13-time All-Star was up for the award after missing most of the 2012 season due to a torn ACL, which he suffered during batting practice prior to a game against the Kansas City Royals on May 3 of that year.
Rivera is the most accomplished closer in the history of the game, racking up an MLB-record 652 saves. He also holds the lifetime record for games finished with 952, and his ERA+ of 205 is the best of all time.