Predicting the Next Crop of Breakout Relievers

Let's play Random Reliever Roulette

Ah, relievers. Baseball’s quirky hodgepodge of characters that teams banish to beyond the ballpark fences, relying on just a rotary phone to reach them during the game. Life as a reliever is hard, arguably one of the hardest roles in all of baseball. I’ve always mentally linked relievers to kickers in football; They aren’t on the field very long, but often appear in the biggest (most watched) spots. That small sample leads to a wide variety of year-to-year performances, and the flaming hot fan reactions to follow.

Noting that volatility, every year, a handful of pitchers pop up seemingly out of nowhere to post strong results out of the ‘pen. Where do they come from? Some are former top prospects, some are veteran journeymen, and almost all are failed starters.

Remember Phil Bickford? A former 1st round pick of the Giants in 2015? He has a 2.59 ERA in over 40 innings of relief for the Dodgers this year. We could talk about Paul Sewald, who has a 1.95 FIP in 44 appearances for the Mariners after spending years as Mets roster fodder. I could also tell you about former Braves and Mariners prospect Luiz Gohara, who is still just 25 and has a 28% K rate in 30 appearances for the Dbacks this season — except in reality he hasn’t pitched since 2018 and was released by the Angels in May of 2020. The point is that some of you believed me and that should say everything you need to know about relievers.

Now that we’ve established how random breakout relievers can be, let’s try our hand at predicting some. This is likely a lesson in futility, but still a fun exercise nonetheless. For the purposes of this article, I am excluding pitchers who have already shown some success in 2021 or have been featured on recent top prospect lists. These are deep cuts; the more random the better!


Enyel De Los Santos, RHP, Philadelphia Phillies


Enyel De Los Santos has been a fixture in Phillies prospect lists for the better part of six years now, acquired from the Padres back in 2017 in exchange for Freddy Galvis. He was always considered a starting pitcher, with all three pitches grading out as at least average. His fastball sits 94-95 but has gotten up to 98 this season in short outings. It also gets tremendous arm-side movement but doesn’t drop like a true sinker. His secondaries include a slider and changeup, using the slider vs righties and the changeup vs lefties. De Los Santos has made 22 appearances for the Phillies this season and has 36 strikeouts in 24 innings. The positives pretty much stop there, with a 5.12 ERA and 5.42 FIP leaving much to be desired. Why is he a prime candidate to break out? He’s seemed to adjust well to bullpen work this season – he’s added a tick of velocity and his walk rate has lowered. His changeup is also a real weapon against lefties, with that ability playing a key role in the age of the 3-batter minimum. His numbers won’t jump off the page and he went unclaimed on waivers in 2020, but he’s got an option year remaining and enough post-hype prospect pedigree to warrant major league chances. This is exactly the type of pitcher we are looking for.


Cole Sulser, RHP, Baltimore Orioles


Sulser has arguably broken out already, with a 3.19 ERA and 31% K-rate in 2021. He was drafted in the 25th round out of Dartmouth by Cleveland in 2013 and dealt to the Rays along with Yandy Diaz in 2018. He pitched very well at AAA in 2019 before being claimed off waivers by Baltimore in November of that year. At age 31, Sulser’s gotten his first full season in 2021, even garnering closer experience for the rebuilding O’s. His strong results against lefties are even more intriguing as the 3-batter minimum rule continues. That opposite-handed success stems from Sulser’s changeup – using a new split-grip that he learned from his brother just last season. It’s uncommon for relief pitchers to heavily use changeups, which are considered one of the hardest (and therefore last) pitches to learn. It’s been working well thus far, with opponents hitting just .125/.192/.188 and whiffing 38.5% of the time against it. With a middling fastball and slider, the changeup is his only dominant pitch. That could be enough to get by in the bullpen, though, and he may have pitched himself into the Orioles’ future plans.


Joe Mantiply, LHP, Arizona Diamondbacks


A 30-year-old journeyman specialist? Now we’re talking! Mantiply was a 27th round pick of the Tigers in 2013. He’s pitched 38 innings over parts of 4 MLB seasons, 30 of which have come with the Dbacks this year. 30 IP in 40 appearances should tell you everything about Mantiply’s role – he is a LOOGY. That role makes sense given the tough angles his low arm-slot and large frame create on lefty hitters. In order to truly break out, Mantiply will need to find success against right-handed hitters as well. Granted, it’s a small 95-pitch sample, but Mantiply’s best offering in 2021 has been the changeup – which as mentioned with Sulser is a decent recipe for reverse-split success. His sinker is still poor, but his changeup has found success against righties and his curveball is successful against lefties. It’s still a long shot, but a breakout is possible if the changeup continues to work.


Ryan Meisinger, RHP, Los Angeles Dodgers


Meisinger, a 27-year-old with 30 major league innings between 3 organizations, had initially caught my eye with his stellar work for the Triple-A Iowa Cubs in 2021. Then while writing this very article, he was claimed by the Dodgers in an under-the-radar waiver trade. That’s exciting for numerous reasons as the Dodgers’ player development has a reputation for turning relievers around. It could certainly just be a way to churn fresh arms, as LA claimed RHP Jake Jewell and LHP Andrew Vasquez that same week, but in a way, that coincidental timing validates my assessment.

Meisinger throws across his body with short arm action and long stride. His 4-seam fastball only sits around 91 mph, well below average for a major league reliever these days. A cursory glance at Meisinger’s fastball characteristics looks similar to that of Alex Vesia and Phil Bickford. Amongst Dodger pitchers, Meisinger’s 6.8ft of extension trails only Bickford (6.9) while its 17.9in of vertical movement ranks third behind Vesia and Walker Buehler’s dominant 4-seamers.  To fully understand the difference in results look no further than Vesia, a poster-child for Vertical Approach Angle. For those unaware, the definition of VAA is simply the angle at which a pitch approaches the hitter. The flatter the better. It’s a known combatant of launch angle and a common feature among breakout pitchers like Bickford and Sewald. VAA standouts are something the Dodgers and other progressive teams are coveting with increasing regularity. Meisinger’s -5.4 degree VAA isn’t great (league average on 4-seamers is -4.9), but given his existing similarities and workable mechanics, it’s possible the Dodgers see Meisinger as a VAA-based development project.


Justin Garza, RHP, Cleveland


Garza was an 8th rounder out of Cal State Fullerton in 2015 and rose through the Cleveland system as a depth arm, splitting time between the rotation and bullpen. He moved to the bullpen full time at Triple-A in 2021 and made his Major League debut with 2.2 innings against the Twins on June 28th. Like the majority of this list, he has a relatively uninspiring profile with just a hint of intrigue. The intrigue for Garza surrounds his sinker, which has been surprisingly effective, despite uh… not sinking. Among pitchers who have thrown at least 100 sinkers in 2021, Garza’s has the worst horizontal movement and 2nd worst vertical movement. While the effects of horizontal movement on sinkers are cloudy, we do know that vertical movement (drop) is the biggest factor in generating ground balls. As such, Garza’s sinker ranks among the league’s lowest in GB%. Along with the sinker that doesn’t sink, Garza mixes in a unique cutter and gyro slider. His cutter spins at a 12:00 axis – perfect spin direction for a 4-seam fastball but relatively uncommon for a cutter. Without going fully in-depth, its spin characteristics are nearly identical to fellow Cleveland reliever Bryan Shaw who has essentially made a career off the cutter. It makes for a unique two-pitch combination, and though the sample size is small Garza could be worth a more in-depth look if the success continues.


R.J. Alaniz, RHP, Cincinnati Reds


Rounding out the list is Reds righty R.J. Alaniz, a 30-year-old journeyman who’s spent time with 5 Major League organizations. At Triple-A in 2021, Alaniz has a 2.83 ERA, 2.31 FIP, and 28% K-rate in 35 innings out of the pen. Even better, he’s yet to allow a HR in those 35 innings. Alaniz made a brief 3 appearance stint at the big league level as well, allowing a run in 2.2 innings. He certainly brings the funk, with a jerky cross-body delivery that can’t be fun to face. His sinker/slider combination doesn’t generate a ton of strikeouts, but its continued effectiveness in limiting hard contact should have use in a middle-relief role. Pitch data is sparse for Alaniz with his small big league sample, but a three-year stint with the Reds should lend some credence, given their focus on pitch design and player development.

Others given consideration (all of which are completely real and definitely not-computer-generated players):

Journeymen in “smart” organizations:

Mike Kickham, LHP, Los Angeles Dodgers

Nick Goody, RHP, New York Yankees

Trevor Gott, RHP, San Francisco Giants

Austin Brice, RHP, Boston Red Sox

Ryan Sherriff, LHP, Tampa Bay Rays

Post-Hype prospects:

Patrick Murphy, RHP, Washington Nationals

Carson Fulmer, RHP, Cincinnati Reds

Braden Shipley, RHP, Cincinnati Reds

Adonis Medina, RHP, Philadelphia Phillies

Patrick Weigel, RHP, Milwaukee Brewers

Pitch Data Darlings:

Ty Tice, RHP, Arizona Diamondbacks

Wyatt Mills, RHP, Seattle Mariners

Vinny Nittoli, RHP, Minnesota Twins

Raynel Espinal, RHP, Boston Red Sox

Jose Quijada, LHP, Los Angeles Angels


Photos from Icon Sportswire | Feature Image by Justin Redler (@reldernitsuj on Twitter)

Natan Cristol-Deman

Natan is a California native and senior at UMass Amherst. He enjoys applying analytics to scouting and player development. You can find him on twitter @natan_cd

3 responses to “Predicting the Next Crop of Breakout Relievers”

  1. Dave F. says:

    As someone who is in an Otteneu points league and looks for efficient and dominant innings, which of these do you like best to breakout next year? Some very intriguing names here.

    • Natan Cristol-Deman says:

      Of these names I’d say De Los Santos (K upside) and Meisinger. Susler has arguably broken out already. Its still a crapshoot though! Use the categories at the bottom as a guide if you want to identify some sleepers in the future.

  2. NickFolesMVP says:

    The Luiz Gohara name drop gave me PTSD

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