Chapman, Diaz win AL, NL Reliever of the Year Awards

Chapman, Diaz win Rivera, Hoffman Awards

By JJ Misiewicz

Photo by Ishika Samant/Getty Images

November 14, 2025

Boston Red Sox closer Aroldis Chapman has won the Mariano Rivera American League Reliever of the Year, and New York Mets closer Edwin Diaz has won the Trevor Hoffman National League Reliever of the year.

Chapman’s 2025

There weren’t a lot of high hopes for Chapman going into 2025, considering his 3.79 earned run average as a Pittsburgh Pirate in 2024. However, Chapman — with the help of PitchCom — has made his 37-year-old self his most dominant form.

Chapman put up career highs in ERA, WHIP, and walk percentage, while still maintaining his high velocity fastball. He was still 98th percentile in average fastball velocity, while being 99th percentile in strikeout percentage and 97th percentile in whiff percentage, according to Baseball Savant.

Diaz’s 2025

Diaz’s tenure in MLB has been very up and down. Every dominant year he has, it’s followed up by a less than superb year. This year was one of Diaz’s dominant seasons.

He finished with a 1.63 ERA and 28 saves in 62 appearances. Diaz finished in the 99th percentile in terms of strikeout percentage and whiff percentage, slightly ahead of Chapman.

Rivera, Hoffman Award Fun Facts

Diaz becomes the second person to win the award three times since the awards inception in 2014, joining Josh Hader. Chapman becomes the eighth person to win the award multiple times, joining Diaz, Hader, Craig Kimbrel, Kenley Jansen, Liam Hendriks, Devin Williams, and Emmanuel Clase.

Chapman becomes the second Red Sox pitcher to win the award, joining Kimbrel when he won it in 2017. The Red Sox became the seventh team to have a player win the award multiple times. The Milwaukee Brewers remain the only team with more than two winners, as they have five in the award’s history, all in the span of 2018-2023. The one non-Brewer to win in that span was Diaz in 2022.

Voting Process

This is not a BBWAA award. Unlike the awards voted on by the BBWAA, there is a nine-person panel, entirely consisting of dominant relievers from baseball’s past, to vote on each award. Those nine are Rivera, Hoffman, Dennis Eckersley, Rollie Fingers, Rich “Goose” Gossage, Lee Smith, Bruce Sutter, John Franco and Billy Wagner. All but Franco are in the Hall of Fame. Each person votes for three relievers in each league, with a 5-3-1 points scale. First place gets five points, second place gets three, third place gets one.