Rivera, the New York Yankees' closer, tore a ligament May 3, 2012, and missed the rest of that season. He returned in 2013 and recorded 44 saves -- fourth most in the major leagues -- while going 6-2 with a 2.11 earned run average.
Rivera announced before the season that he would retire at the end of the year. He completed his career with a major-league record 652 saves.
Liriano, a left-handed starter for the Pittsburgh Pirates, went 16-8 with a 3.02 ERA over 26 starts. He had more strikeouts (163) than innings pitched (161) and hits allowed (134).
He was 6-12 with a 5.34 ERA in 2012 while playing for the Minnesota Twins and Chicago White Sox in 2012. He broke his arm before the 2013 season, which delayed his first appearance for the Pirates until May 11.
Liriano was also the winning pitcher in the Pirates' first post-season game in 21 years, beating the Cincinnati Reds 6-2 in the NL Wild Card Game.
Liriano, who won the AL Comeback Player of the Year Award in 2010, is the first player to win the honor twice.
The Comeback Player of the Year Awards are decided by a vote of the 30 reporters for MLB.com.