MLB Rankings: Top Ten Relief Pitchers for the 2024 Season

All stats within this article come from Baseball Reference, Baseball Savant, and FanGraphs. I reference advanced stats such as K/9, ERA, ERA+, xERA, WHIP, SIERA, FIP, xFIP, Stuff+, Location+, and fWAR in my rankings. To find out what they are, I have attached links that will direct you to an explanation.

Welcome to the eleventh set of my positional rankings for the upcoming MLB season. This list will rank the top ten relief pitchers based on how I believe they will perform in 2024. I will not include any players who are projected to miss the season, such as Orioles’ reliever Felix Bautista.

10: Emmanuel Clase, Cleveland Guardians

Clase is one of the filthiest pitchers in MLB, registering the second-highest Stuff+ (154) among relievers with at least 40 IP last season. Yet, 2023 was a down season for Clase after two years of dominance in 2021 and 2022. He had a 3.22 ERA, career-worst 1.156 WHIP, an uncharacteristic 21.2% strikeout rate, and 12 blown saves. He still lead the league in saves, but it was not an encouraging season for Clase going forward. Despite having elite stuff, Clase wasn’t getting the same results as he was in prior seasons. For example, hitters’ batting average improved from .189 in 2022 to .267 in 2023 against Clase’s cutter. His slider also generated significantly less whiffs, decreasing from 42.7% in 2022 to 31.3% in 2023. Clase gets a spot because he has elite stuff, and he was easily a top five reliever from 2021-2022 — a span in which he 1.33 ERA across 131.1 IP. However, he needs to drastically improve his results in 2024, or otherwise he would lose his spot as a top ten reliever.

9: David Bednar, Pittsburgh Pirates

Since the Pirates acquired Bednar from the San Diego Padres in 2021, he’s been one of the best relievers in baseball. Over three years with the Pirates, Bednar has a 2.25 ERA, 1.063 WHIP, and 11.3 K/9 in 179.2 IP. 2023 was the first year that he led the NL in saves with 39 (tied with Camilo Doval), and he also posted the best ERA of his career, 2.00, across a career-high 67.1 IP. He had 118 Stuff+ with his three-pitch mix featuring a four-seam fastball, curveball, and splitter. His fastball is a legit pitch with 128 Stuff+, and he threw it 58% of the time as opposing hitters batted .188 against it. While his curveball doesn’t grade out as particularly deceptive (91 Stuff+), opposing hitters didn’t fare much better against it (.196 BA). I’ll be watching to see how his curveball does in 2024, but Bednar still deserves a spot with his three-year dominance as a Pirate.

8: Evan Phillips, Los Angeles Dodgers

A career journeyman before arriving in Los Angeles, Phillips became one of the best relievers in MLB during 2022. Over the past two seasons, Phillips has dominated across 124.1 IP with a 1.59 ERA, 0.80 WHIP, and 30.6% strikeout rate. He had 121 Stuff+ in 2023 with his four-pitch repertoire. All four of his pitches (sweeper, cutter, four-seam, sinker) had over 100 Stuff+, but his sweeper stands out with 139 Stuff+. It’s been his most-used pitch since joining the Dodgers, and that’s for good reason. Opposing hitters batted .111 against it, and it garnered a 42.1% whiff rate in 2023. Even though 2023 was a dominant season (2.05 ERA), he did overperform relative to his expected numbers. His xERA was 3.14, and his SIERA was 3.08. He gave up more hard contact, and less groundballs. He could regress if that trend continues.

7: Camilo Doval, San Francisco Giants

A young flamethrower with a fastball that has consistently reached 98 mph throughout his career, Doval, put together an impressive 2023 season. He had a 2.93 ERA, 1.138 WHIP, and 31% strikeout rate in 67.2 IP. Even if his ERA was higher than it was in 2022 (2.53), he improved his strikout rate, WHIP, and walk rate. He’s susceptible to hard contact, but he posted an 88th percentile groundball rate of 52.5%. With 116 Stuff+ in 2023, Doval has a three-pitch mix that includes a slider, cutter, and sinker. According to Stuff+, his cutter was the seventh-best in MLB with 116 Stuff+. This was much better than 2022, a year in which his cutter had 96 Stuff+. It also had much better results. Opposing hitters had a .175 batting average agaist it in 2023 compared to a .340 batting average against it in 2022. This is the type of development that you want to see from a young reliever, and it gives me confidence in Doval going forward.

6: Bryan Abreu, Houston Astros

Abreu has been one of the most underrated relievers for the past two seasons. In a talented Astros’ bullpen, Abreu was the best one. Since 2022, he has a 1.84 ERA and 35.1% strikeout rate across 132.1 innings. 2023 was particularly impressive with a 1.75 ERA, 100 strikeouts, and 241 ERA+ in 72.0 IP. He’s done so well with a two-pitch mix featuring a four-seam fastball and slider. He leaned more into his slider this year after opposing hitters batted .288 against his fastball in 2022. He threw his slider 711 times in 2023, and opposing hitters still couldn’t hit it with a .185 batting average and 41.3% whiff rate. His fastball was also better as a secondary pitch with opposing hitters batting .165 against it. Abreu lacks command with a career walk rate of 11.4%, and his groundball rate decreased dramatically from 2022 (48.5%) to 2023 (37.1%). That’s not ideal for a pitcher that can be susceptible to hard contact, and it prevents Abreu from ranking more highly.

5: Ryan Helsley, St. Louis Cardinals

Helsley missed time in 2023, only pitching in 36.2 innings, but he looked great with a 2.45 ERA, 1.064 WHIP, and 35.6% strikeout rate. This was great to see from a pitcher that missed three months of the season with a forearm strain. It was also encouraging to see that he still had his elite fastball, a pitch that consistently reached 100 mph with 161 Stuff+ last season. Among relief pitchers with at least 30 IP, his four-seam fastball had the fourth-highest Stuff+. He also had the sixth-best slider by Stuff+ (154 Stuff+), and it generated a 52.2% whiff rate. Helsley’s only issue is that he has a career walk rate of 10.6%. Yet, the Cardinals will gladly accept that tradeoff for Helsley’s elite strikeout numbers and stuff.

4: Jhoan Duran, Minnesota Twins

If you’re debating who’s the filthiest pitcher in MLB, Duran might have the strongest case. His four-seam fastball averages nearly 102 mph! He also throws a splitter, dubbed the “splinker” because it has eclipsed 100 mph before. Add a curveball with 145 Stuff+ and you’ve got one of the nastiest pitch repertoires in MLB. Utilizing each of these pitches, Duran has been great during his first two seasons in 2022 and 2023. Through 130 IP, he has a 2.15 ERA, 1.054 WHIP, 33.2% strikeout rate and 7.9% walk rate. 2023 wasn’t as good as 2022 with a higher FIP (3.21) and SIERA (2.78), but Duran has all of the tools to be the best reliever in baseball.

3: Devin Williams, Milwaukee Brewers

One of the premier relievers since his rookie year in 2020, Williams has a 1.89 ERA, 224 ERA+, 39% strikeout rate, and 0.920 WHIP in his career. He’s been automatic in high leverage situations, putting up 36 saves in his first full season as the Brewers’ closer in 2023. Williams throws one of the best changeups in MLB, dubbed the “airbender” because of its high spin rate and unique movement profile. With 41.3 inches of vertical drop and 19.8 inches of horizontal movement — the most horizontal movement among changeups in MLB during 2023 — it’s been a real challenge for hitters. Opposing hitters batted .097 against it with a 42.2% whiff rate in 2023. Like other top relievers, he has a high walk rate (11.7% in career), but there are only a few that top his strikeout rate and career résumé.

2: Josh Hader, Houston Astros

Since his first season in 2017, Hader has been one of the top relievers in baseball. He has a career 2.50 ERA and 42.2% strikeout rate across 388.2 IP. 2023 was business as usual; he had a 1.28 ERA, 36.8% strikeout rate, 1.101 WHIP, and 33 saves in 56.1 IP. As he’s done for the majority of his career, he threw his unhittable sinker over 70% of the time. It had 115 Stuff+ and opposing hitters batted .190 against it. He’ll join a stacked Astros’ bullpen and immediately step in as the closer after signing a 5-year, $95 million contract. He could be the best reliever on this list, but there are two things that hold him back. First, he walked 13% of the hitters he faced last season, ranking among the bottom 5% in MLB. In addition, he was unwilling to pitch outside of save opportunities and go beyond one inning of work. That could change that now he’s been paid, but I’d like to see it first.

1: Edwin Diaz, New York Mets

Even though Diaz didn’t pitch in 2023 because of an unfortunate injury during the World Baseball Classic, he still gets the top spot on my list. His 2022 season was one of the most dominant seasons from a reliever in the past decade. He had a 1.31 ERA, 297 ERA+, 0.90 FIP, 1.11 SIERA, 50.2% strikeout rate, and 0.893 WHIP across 62 IP. Only 2014 Aroldis Chapman had a higher strikeout rate since 2013 (52.5%). Among relievers who pitched at least 50 innings in a season during that time span, his 1.11 SIERA is the third-best in a single season (topped by 2014 Aroldis Chapman and 2016 Andrew Miller). He relies on a two-pitch mix featuring a slider and four-seam fastball. His slider had the second-highest Stuff+ among relievers (160 Stuff+) in 2022. Opposing hitters batted .114, slugged .134, and whiffed 54.7% of the time against it. While it’s unfair to expect him to repeat that type of season, Diaz demonstrated that he is the most dominant relief pitcher in the game today. It’ll be great to have him back in 2024.