Five Future Closers Who Are Breaking Out in MLB Bullpens

No role is more volatile in Major League Baseball than that of a closer.

All eyes are on how the highest-leverage reliever performs in his role and whether he should be trusted to preserve a lead as soon as tomorrow.

Being a closer is both glorifying and demoralizing. It’s a job that every reliever in a major league bullpen is gunning for, since great closers are paid handsomely.

We’ve already seen some household names lose their grip on the job just a couple of months into the season. Raisel Iglesias of the Atlanta Braves has 232 career saves in 11 seasons, but an uncharacteristically poor performance early in the year led to his removal as closer.

The New York Yankees had high hopes for Devin Williams to assert himself as a dominant closer in his first season in the Bronx, but it hasn’t turned out that way. He owns a 5.08 ERA in 28.1 innings and was replaced by Luke Weaver as the closer early on. The two are now sharing the job.

Baseball is unforgiving to relief pitchers. Many have an electric prime, but few have the longevity to become an all-time great.

Here, we’ll discuss who the game’s most promising up-and-comers are for a major league team’s closing role down the road.

Stats updated prior to games on June 23.

What Makes a Pitcher a Great Closer?

The best way to prevent baserunners is by striking out as many batters as possible.

With every ball put in play, there’s a chance that it drops in for a hit. With every ball that drops in for a hit, there’s a chance that the next batter barrels up an extra-base hit and drives in a run. Any time a relief pitcher gives up a run, their ERA skyrockets, due to their small sample of innings.

What does it take for a relief pitcher to rack up strikeouts, even without a starter’s command?

They have to have an above-average fastball. Even if their secondary offerings aren’t stellar or the reliever can’t control them, a good fastball puts pressure on a batter to make decisions faster. This induces chases.

Softer-throwing relievers can work as closers if they have dominant off-speed pitches, but it’s not often that they stick as long-term closers. They have to find their niche if they’re going to be great.

Williams has found success in his career by throwing his fastball at around 94-95 mph, but that’s largely due to a unicorn changeup. Once his average fastball dropped below 94, however, batters started to hit the ball harder much more often.

Iglesias sat at around 96 mph on his fastball about five years ago but has seen that drop to 94.6 mph in his age-35 season. An inflated .333 batting average on balls in play (BABIP) means that he might not be quite so bad for the remainder of the year, but it’s looking less like he’ll be able to regain his closing gig.

The most dominant closers in baseball today throw fuzz. Let’s take a look at the recent saves leaders by year and how hard they have thrown:

Pitch velocity via Statcast.

Carlos Estévez has been an anomaly compared to recent trends, but it’s uncertain whether he’ll be able to sustain this high-leverage success. His 2.14 ERA is great on the surface, but a 4.89 xFIP suggests major regression is coming. He may even lose his job as closer down the stretch, despite being the major league saves leader in late June.

Closers have been great without throwing 98 in the past, but it takes good command and a quality pitch mix. To identify potential future closers that don’t possess the role yet, our best bets are the guys with the most velocity.

Let’s take a look at five young relief pitchers who have what it takes to blow the doors off of the opposition.

Jeremiah Estrada, San Diego Padres

2025 Stats: 33.2 IP, 3.74 ERA, 1.34 WHIP, 31.5% K%, 9.6% BB%, 3.41 xFIP, 0.4 fWAR

Average Fastball Velocity: 97.9 mph

Jeremiah Estrada, 26, technically broke out last season, but a crowded Padres bullpen has prevented him from ascending to the closer role.

After being a relatively unknown Chicago Cub from 2022-23, Estrada was claimed off of waivers by the Padres in 2024. As soon as he joined San Diego, his fastball ticked up 1.3 mph, and he became one of the better relievers in baseball.

In 2024, Estrada threw 61 innings with 94 strikeouts and a 2.95 ERA. He was a revelation.

While Estrada hasn’t been quite as dominant this year as he was previously, his fastball is nearly another tick faster, and he’s missing bats at an elite rate. His walk rate is below average, a problem that many relievers with high-octane fastballs have. That isn’t too much of a concern for Estrada; you can survive with a nine percent walk rate if you miss bats like he does.

Estrada’s repertoire boasts that lights-out fastball (118 Stuff+), an above-average splitter (110 Stuff+), and a decent slider (93 Stuff+). His ability to throw quality pitches and hit his spots earned him an overall 119 Pitching+ grade. Among all players with at least 20 innings pitched this season, Estrada’s Pitching+ grade is one of the top 20 in the game.

The Padres have selected a more experienced option, Robert Suarez, to earn saves now, but Estrada would make a quality closer if given a shot. Estrada is under team control through 2029 and is sure to pitch many more high-leverage innings in his career.

Luis Mey, Cincinnati Reds

2025 Stats: 14.1 IP, 4.40 ERA, 1.26 WHIP, 24.2% K%, 16.1% BB%, 4.18 xFIP, -0.1 fWAR

Average Fastball Velocity: 98.7 mph

Luis Mey, 23, is the most speculative member of this group of potential future closers, given that he has only thrown 14.1 big league innings. Purely based on stuff, Mey looks like a guy who has dominant reliever potential.

Inked by the Reds in the 2018 international signing period for just $50,000 out of the Dominican Republic, Mey looks like a huge acquisition. He ascended through the highest three levels of the minor leagues and into the majors in just 13 months.

The young flamethrower has also posted a 2.60 ERA in 17.1 innings with Triple-A Louisville this season. Indeed, he’s currently back in Louisville right now after he was optioned over the weekend.

The results haven’t been great for Mey thus far in the majors, hence the demotion, but it is hard to make many blanket statements about a player after such a small sample of innings. A 14.1% walk rate in Triple-A tells us that Mey is still learning how to harness his explosive stuff.

Mey doesn’t possess a deep arsenal. He relies solely on a sinker (102 Stuff+) that touches triple digits and a banger slider (134 Stuff+). With a slider that grades out as well as it does, perhaps he’ll soon start to throw it more than 22% of the time. Having two above-average offerings with high velocity is a great foundation for the rookie reliever.

Mey is able to make hitters very uncomfortable. Given that the Reds’ closer role is in flux, he could assume the job by the end of this season if he improves his command at Triple-A.

Daniel Palencia, Chicago Cubs

2025 Stats: 28 IP, 1.93 ERA, 1.00 WHIP, 27.5% K%, 9.2% BB%, 3.41 xFIP, 0.5 fWAR

Average Fastball Velocity: 99.3 mph

Daniel Palencia, 25, has already earned seven saves this season, including the Cubs’ most recent save on June 17.

Even though he has a powerful fastball, nobody expected Palencia to contend for saves this season. The Cubs traded for veteran Ryan Pressly to be their closer to start the season. Porter Hodge, who earned nine saves last season, was expected to take over if Pressly faltered. As for Palencia, he threw just 14.2 MLB innings with a 6.10 ERA and 17.4% walk rate last season.

The door opened for Palencia to take over save opportunities when Pressly struggled to a 7.62 ERA out of the gate and Hodge landed on the injured list. Even though Palencia is still going to compete with those two for saves this season, he looks to be the Cubs’ future closer.

A couple of huge improvements for Palencia have been adding another tick to his fastball velocity this season and cutting his walk rate nearly in half. With an arsenal as explosive as his, Palencia doesn’t have to dance around the zone for chases.

Palencia has four above-average pitches by Stuff+. He throws his four-seamer most often (73% of the time, 111 Stuff+), followed by his slider (22%, 130 Stuff+), and he occasionally sprinkles in a sinker (119 Stuff+), a splitter (142 Stuff+), and a curveball (89 Stuff+). He has decreased his splitter usage greatly this season, but it grades as an outstanding pitch by the model.

With four good pitches, much improved command, and an ability to throw triple-digits, Palencia could be an All-Star in the not-too-distant future.

Randy Rodríguez, San Francisco Giants

2025 Stats: 34 IP, 0.79 ERA, 0.74 WHIP, 38.9% K%, 4.8% BB%, 2.06 xFIP, 1.5 fWAR

Average Fastball Velocity: 97.3 mph

Randy Rodríguez, 25, has been the biggest breakout reliever in baseball this season. He was a serviceable pitcher last year for the Giants (52.1 IP, 4.30 ERA, 53 K), but this year he has been recording video game numbers.

Rodríguez may not have the loudest fastball of this bunch, but he possesses otherworldly command for a reliever with good velocity. Among all pitchers with at least 30 innings pitched this season, only reigning AL Cy Young winner Tarik Skubal has a better walk rate (3.3%) with a higher average fastball velocity (97.9 mph). Only Houston Astros closer Josh Hader has a better K-BB% (34.9%) than Rodríguez (34.7%).

A simple, yet effective arsenal could be a big reason why Rodríguez’s command has been such a strength. After throwing four pitches last season, he ditched his cutter and sinker entirely and is now just a fastball/slider guy.

Rodríguez’s fastball (121 Stuff+) grades out as a well-above-average pitch because he can get ride on it. His slider (116 Stuff+) has been very tough as well, with good horizontal tilt.

The Giants have a talented bullpen, and Rodríguez has been a huge part of it. Ryan Walker (95.7 mph, 4.20 ERA) began the year as the team’s closer but lost his job to Camilo Doval (95.6 mph, 2.06 ERA). If Doval slips up, Rodríguez would likely leapfrog Walker as the team’s next closer.

Despite having earned just one save this season, Rodríguez is making a strong case to be an All-Star. He’s been that effective.

Abner Uribe, Milwaukee Brewers

2025 Stats: 36.1 IP, 1.98 ERA, 1.16 WHIP, 30.4% K%, 10.1% BB%, 3.01 xFIP, 0.6 fWAR

Average Fastball Velocity: 99.9 mph

Abner Uribe, 25, is another arm who technically broke out prior to this year. In 2023, Uribe threw 30.2 innings to a 1.76 ERA with a 100.9 mph fastball. Many pegged him as Milwaukee’s immediate successor to Devin Williams.

Unfortunately for Uribe, last season was nightmarish. He threw just 14.1 major league innings with a 6.91 ERA, and just when he appeared to be getting right in Triple-A, he had to undergo surgery to repair a torn meniscus. This season, however, he’s back to being dominant.

Uribe has done a nice job of cutting down on walks from his brief sample last season (18.2%). He’s also been one of the best in the game at limiting hard contact (2.4% barrel rate). If he’s able to stay around the zone at high velocity and not get barreled, it’s clear that he will keep opposing batters guessing.

Like many of the league’s most effective relievers, Uribe leans on that heavy fastball (his being a sinker) and a slider. Uribe’s slider (129 Stuff+) grades out as his best pitch, and he throws it a healthy 48% of the time. His sinker (110 Stuff+) is also an above-average pitch that is sure to break a lot of bats. He also occasionally flashes a four-seamer (121 Stuff+) that is effective, as well.

Uribe’s slip-up last season opened the door for Trevor Megill (98.8 mph, 2.70 ERA this year) to close, and he has also been very effective. However, Uribe’s velocity is a rarity in this league, and if Megill has a couple of slip-ups, he may not get as long of a leash as other closers would.