Top 10 Best Relief Pitchers for the 2024 MLB Season

Relief pitchers can be some of the most volatile players in Major League Baseball. It takes just one blowup of an outing to raise their ERA through the roof, and it can take quite some time for that number to come back down to earth.

Putting the best relief arms in the game in a list and ranking them is no easy feat. The sheer amount of turnover at the position in any given season is wild. Look at Daniel Bard, Michael Fulmer and someone like Kendall Graveman as prime examples. Each of them was his respective club’s primary closer entering the 2023 season and now no longer has such a hold on the spot.

Next year’s rankings of relievers can – and likely will – look a whole lot different than this list depending on how the upcoming campaign goes for these pitchers. One “down” year can result in removal from such a ranking, so it will be interesting to see where we’re at 365 days from now.

The following rankings were made by our senior staff members at Just Baseball. Jack McMullen, Peter Appel, Aram Leighton, Ryan Finkelstein, Leo Morgenstern and Colby Olson each created their top player lists at each position, and we took the composite average score to set our 2024 rankings.

Medically Disqualified: Félix Bautista (BAL)

There’s no telling just how high Bautista would be featured on this list if he wasn’t injured. The right-hander’s last appearance in 2023 came at the end of August and ended with him leaving the game due to a UCL injury.

As is usually the case with injuries like his, Bautista went under the knife and will miss all of the 2024 campaign as he recovers from Tommy John surgery.

The 6-foot-8 behemoth has rather rapidly turned himself into one of the game’s best relief pitchers. Last season, he registered a 1.48 ERA in 56 games with 33 saves, a 1.88 FIP and 280 ERA+. Along the way, he earned his first All-Star Game selection, finished 11th in the AL Cy Young voting and led all qualified relievers in strikeouts with 110. We have not seen the last of him.

Honorable Mentions: Pete Fairbanks (TB), José Alvarado (PHI)

The fact that Fairbanks and Alvarado are only able to crack the list as honorable mentions speaks volumes about the high-end bullpen talent around the game.

Since 2020, Fairbanks has been utterly dominant at the back end of the Rays’ bullpen. Last year, he became the club’s full-time closer and earned 25 saves in 49 appearances, finishing the season with a 2.58 ERA and 162 ERA+. He is a true flamethrower who threw his fastball an average of 99 mph in 2023, good for the 98th percentile in fastball velocity (per Baseball Savant).

Alvarado, 28, is an ex-teammate of Fairbanks who now resides in the back end of the Phillies’ bullpen. The left-hander had a 1.74 ERA in 42 outings last year, and, like Fairbanks, finished in the 98th percentile in fastball velo.

10. Andrés Muñoz (Seattle Mariners)

Age: 25

2023 Stats: 52 G, 13 SV, 49.0 IP, 2.94 ERA, 2.70 FIP, 12.3 K/9, 4.0 BB/9, 1.3 fWAR

Over the past two seasons, the Mariners have been finding out firsthand what a healthy Muñoz is capable of. The right-hander missed all of 2020 and ’21 thanks to Tommy John surgery, but has bounced back in a big way in the years since.

Since returning from TJ, Muñoz has made 116 appearances and posted a sparkling 2.68 ERA. He is a strikeout machine who rarely ever allows the long ball (seven in the past two years) and ranks near the top of the league in nearly every major pitching category, per Statcast.

The Mariners love everything about Muñoz, and it’s not difficult to see why. He’s still only 25 years old and there’s a sense of some still-untapped potential in his arm, despite the fact that he’s already becoming one of the best relievers in the game.

Signed to an extremely team-friendly extension in December of 2021, Muñoz is technically set to hit free agency at the conclusion of the upcoming season, but the Mariners hold team options over him for each of the next three years. There’s little doubt he spends every second of that time in a Mariners uniform.

9. Alexis Díaz (Cincinnati Reds)

Age: 27

2023 Stats: 71 G, 37 SV, 67.1 IP, 3.07 ERA, 3.52 FIP, 11.5 K/9, 4.8 BB/9, 1.7 fWAR

The younger brother of Edwin Díaz, Alexis has provided the Reds with a lethal closer in each of the past two seasons. In 2023, he earned 37 saves (fourth most in the majors) in 71 appearances while posting a 149 ERA+.

Díaz, 27, leans on a nasty slider-fastball combo to dominate the opposition, and it works like a charm. Last season, hitters only managed to post a .142 batting average against the offering, and he finished the year in the 98th percentile in breaking ball run value (per Savant) because of it.

Long-term, it will be important for Díaz to hone in on his command and walk fewer batters, but he boasted a strikeout percentage over 30% last year, and he seems to be well on his way to a long and promising career as one of the game’s best closers.

8. Camilo Doval (San Francisco Giants)

Age: 26

2023 Stats: 69 G, 39 SV, 67.2 IP, 2.93 ERA, 2.77 FIP, 11.6 K/9, 3.5 BB/9, 1.9 fWAR

Doval is still so young, but it’s clear that his future is full of promise. After he made the All-Star Game and led the National League in games finished and saves last season, things are looking good for the Giants at the tail end of their ‘pen.

The right-hander, like many others on this list, regularly hits triple digits with his fastball and is must-see TV whenever he takes the mound. Followers of the Giants had to deal with a few “down” months from him this past year, but the general consensus is that when Doval takes the mound, the game’s already over.

There’s a strong chance that some of the early difficulties Doval faced in 2023 were thanks to a combination of his inclusion in the World Baseball Classic and some of the new rules in the game – primarily the pitch clock. Once again, he will be a heavily relied-upon piece in 2024, and he seems to be just getting started.

7. David Bednar (Pittsburgh Pirates)

Age: 29

2023 Stats: 66 G, 39 SV, 67.1 IP, 2.00 ERA, 2.53 FIP, 10.7 K/9, 2.8 BB/9, 2.3 fWAR

Bednar is coming off of a season in which he posted the third-highest fWAR in the game amongst relievers. The righty has been a consistent bright spot on an otherwise underwhelming Pirates squad.

Unlike Doval, Bednar only had a small stretch last year in which he wasn’t a dominant force in the ninth inning. The two arms were tied for the most saves in the NL with 39, but what makes Bednar’s case even more intriguing is the fact that he went essentially the entire month of May without any saves (he had one).

Currently mired in trade rumors, there’s a chance Bednar’s days for playing on a cellar-dwelling team are coming to a close. He could be one of the top available relief arms this season, so his name will be one to watch in more than one way come July.

6. Bryan Abreu (Houston Astros)

Age: 26

2023 Stats: 72 G, 5 SV, 72.0 IP, 1.75 ERA, 2.98 FIP, 12.5 K/9, 3.9 BB/9, 1.5 fWAR

It is shocking to realize that Abreu, who was one of the very best relievers in the game last year, is not even the best bullpen arm on his own team. Still, the right-hander was excellent in 2023, finishing 4th in the AL in LOB%, 6th in K%, 5th in ERA and 10th in WAR amongst relief pitchers.

To round out the regular season, Abreu did not allow a single earned run from July 15 on. This spanned a whopping 27 scoreless outings in a row for him. What more do you need to see? In that time, he struck out 34 batters and allowed just 11 hits across 27.2 frames, while batters hit just .125 against him.

Abreu then did not allow a run in three ALDS appearances against the Twins. While he surrendered four runs across six games in the ALCS against Texas, he still struck out seven batters and remained one of the most trustworthy arms for Dusty Baker.

In 2024, he will not be in line for many save opportunities thanks to the super-bullpen that’s been built around him, but Abreu will continue to get as many high-leverage innings as he can handle, because at this point, he’s earned it.

5. Emmanuel Clase (Cleveland Guardians)

Age: 26

2023 Stats: 75 G, 44 SV, 72.2 IP, 3.22 ERA, 2.91 FIP, 7.9 K/9, 2.0 BB/9, 1.7 fWAR

After two consecutive sub-2.00 ERA seasons in Cleveland, Clase experienced a slight regression in 2023. Of course, he still found a way to lead the AL in games finished and saves, but this doesn’t mean he was perfect. In fact, Clase led the AL in both saves and blown saves. His 12 blown saves were the most a pitcher has had since 2006 when Ambiorix Burgos of the Royals did the same.

Batters had a much easier time hitting Clase’s cutter, which is typically his best offering, in 2023. The pitch allowed just a .186 batting average against in 2022, but that number rose to .267 in 2023.

His slider still allowed just a .181 BAA in 2023, but it seems that Clase saw a decline in his overall numbers due to the fact that hitters simply caught on to his game.

It’s tough to rank a pitcher who, at times, looks like one of the best relievers we’ve seen in decades, but at other times leaves fans in Cleveland holding their breath while he’s on the mound.

Last year, Clase became the first closer in Guardians’ franchise history to record 40 saves in at least two seasons, which is a testament to how dominant he can be when he’s on. Since 2022, he leads the league in saves, appearances, and fWAR. Why he’s included this high on this list is obvious, but he has the potential to rise even higher.

4. Josh Hader (Houston Astros)

Age: 29

2023 Stats: 61 G, 33 SV, 56.1 IP, 1.28 ERA, 2.69 FIP, 13.6 K/9, 4.8 BB/9, 1.7 fWAR

There is virtually nothing left for Hader to do to cement himself into the conversation for “best relief pitcher of his time”. The southpaw returned to form in a huge way last year, just in time for his first trip to free agency.

Of course, Hader landed with the Astros, the team that traded him to the Brewers in 2015 – just before he became a big league superstar. His contract set a record for the largest guarantee (present-day value) in MLB history for a relief pitcher.

There was never a doubt that someone like Hader would be the one to break such a record. He finished this past season with a sub-2.00 ERA, the second time he’s done such a thing. He has also posted a sub-3.00 ERA five times in seven years.

Consistently striking out upwards of 12-13 batters per nine innings, Hader remains an elite K artist. He sat 13.6 K/9 last year and allowed just 5.1 hits per nine, which is the lowest rate he has posted in years.

Hader’s devastating fastball, mixed with a huge, sweeping slider, is the key to his success. Last season he threw his heater 73% of the time and allowed just a .190 BAA. For reference, the BAA off of the fastball was at .241 the year before. He continues to make the necessary adjustments to keep hitters off balance, which is one of the primary reasons he’s one of the very best this game has to offer.

3. Devin Williams (Milwaukee Brewers)

Age: 29

2023 Stats: 61 G, 36 SV, 58.2 IP, 1.53 ERA, 2.66 FIP, 13.4 K/9, 4.3 BB/9, 1.8 fWAR

Williams, the man who replaced Hader as Milwaukee’s closer, continued to do his thing in 2023. The right-hander posted his fourth consecutive sub-3.00 ERA season last year and has shown no real signs of slowing down.

Armed with one of the best changeups we’ve ever seen, Williams rather easily won his second NL Reliever of the Year Award in 2023. He allowed the opposition to hit just .129 off of him, too, which was easily the best in all of baseball. At the same time, he struck out nearly 38% of the batters he faced, which was good for fourth in the league.

The big question, of course, is whether the Brewers will trade Williams before they have to seriously pay him. With the addition of Rhys Hoskins, it seems that Milwaukee will make another attempt at “going for it” rather than blowing it all up. However, it would not be a shock to see the Brew Crew seek out a swap for Williams rather than paying him the massive contract he deserves in the coming years.

2. Jhoan Duran (Minnesota Twins)

Age: 26

2023 Stats: 59 G, 27 SV, 62.1 IP, 2.45 ERA, 3.21 FIP, 12.1 K/9, 3.6 BB/9, 1.0 fWAR

There is perhaps no relief pitcher better set up for long-term success than Duran. At just 26 years of age, the right-hander already has two straight seasons of being one of the best in the game under his belt. Getting a shot at being the Twins’ full-time closer for the first time last year, Duran notched 27 saves while regularly throwing some of the nastiest heat you’ll ever see.

Duran is still pre-arbitration and is not currently set to hit free agency until the conclusion of the 2027 season. The Twins are going to have one of the best pitchers in the game at a bargain rate for the next four years, which is truly an embarrassment of riches.

Outside of a down month of July in which he had a 6.52 ERA in 10 outings, Duran was absolutely dominant in 2023. He allowed four earned runs or fewer in every single month of the season outside of July, when he allowed seven. He followed this up with two scoreless innings in the Wild Card Series against the Blue Jays and then two more in the ALDS against the Astros.

The Twins are fresh off of a year in which they won the AL Central crown, so hopefully Duran’s days of pitching in the playoffs are only just beginning.

1. Edwin Díaz (New York Mets)

Age: 30

2022 Stats (Injured in ’23): 61 G, 32 SV, 62.0 IP, 1.31 ERA, 0.90 FIP, 17.1 K/9, 2.6 BB/9, 3.0 fWAR

The 2023 season was shaping up to be one of the best we’ve ever seen out of a relief pitcher for Díaz. In heartbreaking fashion, he sustained a nasty knee injury in the WBC that took him out for the entire year before it even began. This was just a few months after he signed a record-breaking contract in free agency, which added salt to the wound.

Losing such a force at the back end of the bullpen was a huge blow for the Mets, and it was one they couldn’t really recover from. It’s not that the absence of Díaz alone caused them to finish 12 games under .500, but he surely would’ve helped to better the club’s 4.45 bullpen ERA on the season.

When he was last healthy in 2022, Díaz struck out more batters than any other reliever (118), had a higher fWAR (3.0) than any other bullpen arm, and had an unreasonably solid 0.90 FIP, which is unheard of.

Looking ahead, there’s no doubt why four of our six panelists voted Díaz as the top reliever in the game. He has such an overpowering arsenal and is one of the best strikeout artists of his time. He has been so consistently dominant on the mound for nearly a decade now, so it’s exciting to know that we could be seeing a legitimate Hall of Fame talent right before our eyes.