2025 MLB Reliever of the Year Odds

Making a deep run into the MLB postseason without a strong bullpen is an almost impossible task. No matter how much the game changes, one thing that won’t change is the need for a high-level closer, but finding one is far easier said than done.

Being able to breathe a sigh of relief when a certain reliever enters a tight game is something only fans from certain teams can experience this season. Those relievers who bring a sense of calm to a hectic situation are also fighting for the Reliever of the Year Award. After Emmanuel Clase and Ryan Helsley won the 2024 Reliever of the Year award, we'll keep bettors up to date on the 2025 Reliever of the Year award.

2025 National League Reliever of the Year - Best Odds

2025 NL Reliever of the Year Odds Comparison - Top 5 Contenders

Odds as of July 9, 2025

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Robert Suarez (SD Padres): In his first full season as the Padres' closer, Robert Suarez quickly proved he was one of the best in baseball. In 42 save opportunities in 2024, Suarez converted 36 of them, while also racking up 59 strikeouts and boasting a 2.77 ERA in 65 innings. To start the 2025 season, Suarez has converted 26 of 29 save opportunities and is pitching to a 3.72 ERA and 2.31 FIP, while holding opponents to a .213 batting average. Those numbers were also enough to earn the Padres' closer a spot in the All-Star game.

Edwin Diaz (NY Mets): The 2024 season was Edwin Diaz's worst season as the Mets' closer. After blowing seven saves and pitching to a 3.52 ERA, the Mets desperately needed Diaz to return to his old form if they were going to make a World Series run. So far, Diaz has answered the call to step up, converting 18 of 19 save opportunities while pitching to a 1.75 ERA with 54 strikeouts in 36 innings.

Ryan Helsley (STL Cardinals): Ever since 2022, the man they call "Hellz Bellz" has been a force out of the Cardinals' bullpen. In his first full season as the Cardinals' lone closer, Helsley recorded a career-high 49 saves in 53 save opportunities. Helsley finished the year with 66.1 innings, in which he racked up 79 strikeouts and posted a 2.04 ERA and 2.41 FIP, which were enough to earn him his first Reliever of the Year honors. Coming off an award-winning season, Helsley has started 2025 by going 18-23 on save opportunities, sporting a 3.19 ERA and a 3.66 xFIP.

2025 American League Reliever of the Year - Best Odds

2025 AL Reliever of the Year Odds Comparison - Top 5 Contenders

Odds as of July 9, 2025

Current Favorites

Josh Hader (HOU Astros): Winning Reliever of the Year would be nothing new to Josh Hader, but if he can get the job done this season, it would be the first time he has done it in the American League. Last year, Hader had some struggles with home runs, but that has not been the case this season, as he is boasting a 2.38 ERA with 63 strikeouts in 41.2 innings. Not to mention, the lefty is also 25 for 25 on save chances.

Andres Munoz (SEA Mariners): Munoz took over as the full-time closer for the Mariners last season and instantly became one of the more dominant closers in the AL. As he transitions into his second season as a full-time closer, he has not slowed down at all, converting 21 of his 26 save chances while punching out 45 hitters in 34 innings of work.

Aroldis Chapman (BOS Red Sox): Throughout his career, Aroldis Chapman has been on quite a few teams, but one thing that doesn't change is his fastball. In his first season with the Red Sox, Chapman has gone 15-16 on save opportunities and recorded 53 strikeouts in just 36 innings. If Chapman keeps his current pace, he could also post the lowest opponent batting average he's had since 2014, when he held hitters to a .121 average.

Past Winners

AL Winners

NL Winners

Understanding WPA: The Stat That Rewards Clutch Relief

There are a lot of electric and talented relievers across the MLB, so bettors need more than just ERA and saves to know how to separate the genuine contenders for Reliever of the Year. There are a few advanced metrics that can help, such as FIP. However, two indicators that are often overlooked but are very valuable are Win Probability Added (WPA) and the leverage index.

These metrics go beyond impressive stats to show which pitchers excel when it matters the most. WPA is a measurement of how a pitcher's performance shifts their team’s odds of coming away with a victory in real time. As for the leverage index, this metric measures how “stressful” or high-leverage a situation is. 

In 2024, Emmanuel Clase led the MLB with a 6.29 WPA, while Kirby Yates, who finished second in the AL voting, had the second highest WPA, and Ryan Helsley, who won the award in the NL, had the fourth highest. Some years, relievers who lead the league in saves may also be ranked in the top 5 in WPA, but other years, relievers who don’t lead the league in saves may still be able to win Reliever of the Year due to their WPA. 

Back in 2022, Edwin Diaz had nine fewer saves than NL saves leader Kenley Jensen, but he was 7th in the league in WPA and had the highest Championship WPA among relievers that season.

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