Buster Olney ranks MLB's top 10 relievers -- and there's no doubt about who's No. 1

Spring training camps are underway, which means it is time to look at the state of baseball. As part of our 2026 MLB season preview, ESPN's Buster Olney surveyed those around the industry to help him rank the top 10 players at every position as part of his annual positional ranking series.

Today, we rank the best of the best relievers.

The objective of this exercise is to identify the best players for the 2026 season, not who might be best in five years or over their career. We will roll out a position per day over the next two weeks. Here's the schedule: starting pitchers (Monday), catchers (Wednesday), first basemen (Thursday), second basemen (Friday), third basemen (Feb. 23), shortstops (Feb. 24), corner outfielders (Feb. 25), center fielders (Feb. 26) and designated hitters (Feb. 27).

The Padres had checked in with the Athletics on Mason Miller's availability in the midst of the 2024 season, and then again last June. As Padres general manager A.J. Preller recalled in a recent conversation, there didn't seem to be any traction for a possible deal. But about a week before the trade deadline, with A's GM David Forst talking to a handful of teams about Miller, Preller indicated he'd be open to including 19-year-old shortstop Leo De Vries, considered one of the best prospects in baseball.

Typically, executives are not willing to surrender high-end position prospects for relievers. This was different, Preller felt. "When you're talking about someone like Mason Miller," he said, "no one should be off the table."

Forst had been focused on structuring a potential Miller trade around pitching, but that immediately shifted. "Leo was a difference-maker," he recalled.

With the possible anchors of a deal in place, the two sides rounded things out and completed the trade, and in the last two months of the season, Miller was everything the Padres could have hoped for, striking out 45 of the 83 batters he faced in the regular season. After he joined the Padres, opponents batted .096 against him. In San Diego's playoff series against the Cubs, he whiffed eight of nine batters, hitting the one he didn't strike out. His average fastball velocity of 101.2 mph was the highest for any reliever last season.

There is great debate about who is the best starting pitcher in baseball. But among relievers, there's not really any doubt who is No. 1.

Top 10 relief pitchers

1. Mason Miller, San Diego Padres

Preller met Miller when the pitcher was in college, before the A's drafted him in the third round in 2021. And besides Miller's physical talents, what stood out to him was his presence -- the leadership qualities he saw. This is not typical among relief pitchers, Preller acknowledged, but the Padres have something of a history with that, with Hall of Famer Trevor Hoffman, and later, Craig Stammen, whom Preller recently picked to be his manager. The Padres started to see some of that from Miller at the end of last year, Preller said.

2. Edwin Diaz, Los Angeles Dodgers

Twelve relievers combined for the 46 saves the Dodgers recorded last season, as injury and inconsistency forced manager Dave Roberts to cycle through an army of relievers in the closer role. The Dodgers' response: outbid the rest of the industry for the best available reliever this offseason. Last year was the second best of Diaz's career -- he allowed only 37 hits and struck out 98 in 66⅓ innings, and he held opposing hitters to a .502 OPS.

3. Jhoan Duran, Philadelphia Phillies

Duran's dramatic, spidery entrance into games and his power stuff (average fastball: 100.6, the second fastest in the majors) obscures the difficulty hitters have in doing any kind of damage against him. He whiffed 80 hitters in 70 innings, and walked only one in his 20 innings with the Phillies, but he also had an absurd groundball percentage of 65%, the highest for any reliever. His kryptonite is the running game: He allowed 13 steals in 14 innings last year.

4. Aroldis Chapman, Boston Red Sox

For the first time in his career, Chapman was able to command his fastball more consistently on the inner half of the plate, and he regained the degree of dominance he had in the first half of his career. At age 37, Chapman allowed the lowest walk rate of his career (6.6%), for a staggering OPS+ of 351. The Red Sox worked out a $13.3 million extension with him late in the regular season, which could turn out to be one of the biggest bargains of the upcoming season.

5. Cade Smith, Cleveland Guardians

The Guardians could not have had a better Plan B following Emmanuel Clase being placed on leave last year than what they have in Smith, who might be the closest of his generation to matching the stoic demeanor of Mariano Rivera. Through success or the occasional failure, opposing hitters see the exact same in his response. If the baseball thing ever stops working for him, Smith could be a Buckingham Palace sentry. He has 207 strikeouts in the first 149 innings of his career.

6. Andres Munoz, Seattle Mariners

Munoz has had four straight years with an ERA+ of at least 135, and last season was his best: Munoz punched out 83 hitters in 62⅓ innings and held opposing hitters to a .493 OPS. His saves can be heart pounding because of his walk rate (11%), but he surrendered just two homers in 64 regular-season appearances.

7. Abner Uribe, Milwaukee Brewers

Uribe had an ERA+ of 249 in his first full season in the big leagues, and the right-hander's funky delivery and breaking stuff make him a nightmare for hitters. Last year, righties batted .211 against him, with a .268 on-base percentage, but lefties fared even worse as he allowed just one homer and a .171 average in 132 plate appearances against them.

8. Robert Suarez, Atlanta Braves

Suarez didn't make his major league debut until after his 31st birthday. Over his first four full seasons, he established himself as one of baseball's most consistent relievers, which is why Atlanta, needing help in its bullpen, invested a three-year, $45 million deal in the right-hander.

9. Devin Williams, New York Mets

Williams makes the crosstown jump to the Mets and rejoins David Stearns, who ran baseball operations in Milwaukee when Williams' changeup became legendary there. Williams' inconsistency in his one season with the Yankees prompted Aaron Boone to move him out of the closer's role -- then in and then out again -- but Williams allowed earned runs in only two of his last 19 regular-season appearances.

10. Josh Hader, Houston Astros

Hader moved a few spots down this list following the recent news that he's a little behind in his throwing program because of biceps inflammation, and it's unclear when he'll rejoin the Houston bullpen. Remember, his last appearance of 2025 was Aug. 8. Hader, 31, is building a strong case for the Hall of Fame, given his level of dominance -- he's had two seasons in his career in which his Adjusted OPS was over 300, and he's allowed 282 hits in 512⅓ innings over his first nine seasons.

Honorable mentions

Garrett Whitlock, Red Sox: It was clear from his first conversation with reporters this spring that Whitlock is beating himself up over his playoff performance, but Boston probably wouldn't have gotten as far as it did without him.

Adrian Morejon, Padres: He allowed only 49 hits and two homers in 73⅔ innings. He'll be a free agent after the upcoming season.

David Bednar, New York Yankees: Bednar might not have the best stuff of any reliever, but he seems to possess a perfect temperament for New York.

Bryan Abreu, Astros: Houston might need Abreu in the closer's role at the outset of the upcoming season.

Tyler Rogers, Toronto Blue Jays: Rogers' command is absurd: He led the majors with 81 appearances last season and walked only seven hitters. Right-handed batters had 155 plate appearances against him and drew one walk (and hit one homer.)

Ronny Henriquez, Miami Marlins: Miami picked Henriquez up on waivers from the Twins last February and he went on to have a spectacular season with the Marlins, posting an ERA+ of 199.

Brad Keller, Phillies: Keller's success with the Cubs last year prompted the Phillies to work out a two-year, $22 million deal with the right-hander.

Gabe Speier, Mariners: Seattle added Jose Ferrer in an offseason trade, which should take some pressure off Speier, who worked in 76 games in the regular season and seven more in the postseason.

Jeremiah Estrada, Padres: Suarez left San Diego as a free agent, but Estrada is the third Padre on this list. Stammen's bullpen in his first season as manager should be excellent.

Griffin Jax, Tampa Bay Rays: He wasn't as overpowering last year as he was in 2024, but he still averaged 13.50 strikeouts per nine innings and improved after Tampa Bay acquired him in midseason.

Randy Rodriguez, San Francisco Giants: He'll likely miss the entire '26 season after undergoing an elbow reconstruction, but he earned a mention on this list with his performance last year.