2025 MLB Reliever of the Year Odds

Making a deep run in 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 24, 2025

Current Favorites

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 21 of 23 save opportunities while pitching to a 1.55 ERA with 61 strikeouts in 40.2 innings.

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 29 of 32 save opportunities and is pitching to a 3.46 ERA and 2.23 FIP, while holding opponents to a .205 batting average. Those numbers were also enough to earn the Padres' closer a spot in the All-Star game.

Trevor Megill (MIL Brewers): While the divisional race is going to continue to be a battle, the Milwaukee Brewers have jumped the Cubs for first place in the NL Central. The Brewers' bullpen has played a significant role in their success, and Megill is the focal point of that bullpen. In 26 save opportunities, Megill has converted 24 of them, while also recording a 2.27 ERA and holding opponents to a .189 average.

2025 American League Reliever of the Year - Best Odds

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

Odds as of July 31, 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 2.22 ERA with 73 strikeouts in 48.2 innings. Not to mention, the lefty is also 28 for 29 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 24 of his 30 save chances while punching out 54 hitters in 41 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 19-21 on save opportunities and recorded 62 strikeouts in just 42 innings. If Chapman keeps his current pace, he could also post the ERA of his career, as his is currently sitting at 1.29.

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 the 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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