Major League Baseball Reliever of the Year Award

annually honors its best relief pitchers in the American League and National League with the Mariano Rivera AL Reliever of the Year Award and Trevor Hoffman NL Reliever of the Year Award, respectively. The awards are named after former relievers Mariano Rivera and Trevor Hoffman, who played their entire careers in the respective leagues. First issued in 2014, the awards replaced the Delivery Man of the Year Award, which had been presented since 2005.
The Reliever of the Year Awards are based on the votes of a panel of retired relievers. Each voter selects three pitchers for each league based solely on their performance in the regular season; a 5-3-1 weighted point system is used to determine the winner. At its inception in 2014, the panel consisted of the top five relievers in career saves at the time—Rivera, Hoffman, Lee Smith, John Franco, and Billy Wagner—and the four living relief pitchers who were in the Hall of Fame: Dennis Eckersley, Rollie Fingers, Goose Gossage, and Bruce Sutter.
The Reliever of the Year Award winners had all been closers until 2018, when Josh Hader of the Milwaukee Brewers won as a setup man; he later won the NL title in 2019 and 2021 as a closer. The inaugural All-MLB teams named both of the award winners in 2019. In 2020, the Brewers' Devin Williams became the first rookie and the first reliever with no saves to win the award in either league.
Since 2017, MLB has also issued a Reliever of the Month Award.

Winners

Trevor Hoffman NL Reliever of the Year

Year	Player	Team	SV	ERA	WHIP	K	IP	Ref
2014		Atlanta Braves	47	1.61	0.91	95
2015		Pittsburgh Pirates	51	2.23	0.93	62
2016		Los Angeles Dodgers	47	1.83	0.67	104
2017		Los Angeles Dodgers	41	1.32	0.75	109
2018		Milwaukee Brewers	12	2.43	0.81	143
2019		Milwaukee Brewers	37	2.62	0.81	138
2020		Milwaukee Brewers	0	0.33	0.63	53	27
2021		Milwaukee Brewers	34	1.23	0.84	102
2022		New York Mets	32	1.31	0.839	118	62
2023		Milwaukee Brewers	36	1.53	0.920	87
2024		St. Louis Cardinals	49	2.04	1.100	79
2025		New York Mets	28	1.63	0.874	98

Mariano Rivera AL Reliever of the Year

Year	Player	Team	SV	ERA	WHIP	K	IP	Ref
2014		Kansas City Royals	46	1.44	0.91	90
2015		New York Yankees	36	2.04	0.86	100
2016		Baltimore Orioles	47	0.54	0.84	74	67
2017		Boston Red Sox	35	1.43	0.68	126	69
2018		Seattle Mariners	57	1.96	0.79	124
2019		New York Yankees	37	2.21	1.11	85	57
2020		Oakland Athletics	14	1.78	0.67	37
2021		Chicago White Sox	38	2.54	0.73	113	71
2022		Cleveland Guardians	42	1.36	0.729	77
2023		Baltimore Orioles	33	1.48	0.918	110	61
2024		Cleveland Guardians	47	0.61	0.660	66
2025		Boston Red Sox	32	1.17	0.701	85