Boston Red Sox Reliever of the Year (2025)

With the 2025 season officially over, it is time to look back at what was one key strength of the Boston Red Sox, which was their bullpen. This past season, the Red Sox had the best bullpen ERA in the American League and the second-best in all of major league baseball at 3.41 while tossing 585 1/3 innings. Across the year, the bullpen went a combined 36-29 with 45 saves and struck out 554 batters, helping the Red Sox return to the playoffs for the first time since 2021.

Now, it’s time to look at the three most valuable relievers from the team and give them their deserved flowers. Of course, only one will be named the Reliever of the Year, but the bullpen as a whole deserves a lot of credit for the success the team found in 2025.

#3) Steven Matz 21 games, 21 2/3 innings pitched, 12 strikeouts, 2.08 ERA

Matz may not have pitched as much as other members of the bullpen, but after coming over at the trade deadline from St. Louis, he became an integral part of the relief corps. While both Greg Weissert and Justin Wilson struggled at times, Matz remained a key piece for manager Alex Cora. In 11 August games with the Red Sox, Matz allowed just one run in 12 1/3 innings. And while those numbers increased slightly in nine September games (four earned in nine innings), Matz still provided a reliable left-handed presence in the bullpen in a time of need, as Brennan Bernardino got placed on the injured list and Wilson was up and down. Overall, on the season, Matz went 5-2 in 53 games between the Red Sox and Cardinals with a 3.05 ERA. He also struck out 59 batters in 76 2/3 innings. He is due to be a free agent, though it wouldn't be a surprise to see the Red Sox prioritize a new contract with him over the winter.

#2) Garrett Whitlock 62 games, 72 innings pitched, 91 strikeouts, 2.25 ERA

This was a tough choice. If I could pick two winners, this award would be shared between Whitlock and Chapman, as the duo were a fearsome 1-2 punch in the back of the bullpen for the Red Sox. Whitlock looked even better than his 2021 self despite a lower ERA in his rookie season. This was in part thanks to his strikeouts per nine innings climbing to a career high at 11.38, along with the righty cutting back on home runs by only allowing two all season. For 2025, Whitlock struck out opponents at a 31.1% rate while opponents only hit .205 against him. He was especially lights out when it mattered most, as Whitlock allowed just a single run across 21 2/3 innings in August and September. In that same span, he struck out 26 batters and walked just five. In high-leverage situations, Whitlock remained poised and collected, as batters hit just .200/.296/.290 off of him while striking out 36 times.

#1) Aroldis Chapman 67 games, 61 1/3 innings, 85 strikeouts, 1.17 ERA, 32 saves

As mentioned with Whitlock, this was a tough choice. While Whitlock had more innings pitched and more strikeouts, what Chapman did this season at 37-years-old is remarkable. Not only did he turn back the clock, but the closer had what might be the best season of his career. Using fWAR, he had the third-highest of his career at 2.6 (if we use bWAR it would be 3.5 and the highest of his career). In his 61 1/3 innings pitched, Chapman allowed just nine runs, eight of them earned, to score all season. Not a month, but the entire season. It harkens back to Koji Uehara’s 2013 season at the age of 38. From June through the end of September, Chapman allowed just three earned runs in 38 1/3 innings while striking out 54 batters and walking just seven. He struck out 12.47 batters per nine innings and had the lowest walk rate of his career at 6.6%. His strikeout rate may not have been the highest of his career, but it was still a whopping 37.3%. Opposing batters hit just .131 against him, the second-lowest mark against him in his career, and he put together the lowest WHIP of his career at 0.70. With 32 saves this season, Chapman provided stability in the closer’s role that fans feared would be missing without Kenley Jansen. 

From his entrance blasting La Vida Es un Carnaval while a tribute to Luis Tiant played on the jumbotron, to his iconic stare at the opposing batter who made the final out, Chapman brought an intensity and aura to the closer’s role that had been sorely needed in Boston for quite some time.

What did you think about our choices? Do you agree, or do you feel someone was snubbed? Leave your thoughts down below in the comments!