Starter Prospects that Could be Impact Relievers in 2021

March 17, 2021

Marc Hulet looks at 15 starting pitcher prospects that could become impact relievers for the 2021 season and ease the workloads of their clubs' veteran starters without a dropoff in performance.

In many ways, Major League Baseball is getting back to normal in 2021. Most importantly for sports fans and fantasy baseball fanatics, this means that the season will be 162 games after experiencing a stunted 2020 season.

However, the sudden spike back to 162 games from 60 contests creates headaches for MLB managers. Lance Lynn led all pitchers last season with 84 innings pitched. Only two other pitchers — German Marquez and Kyle Hendricks — threw more than 80 innings. Another 14 hurlers threw 70-79.2 frames. In a full season, most hurlers are eyed for 150-200 innings which would be a year-over-year increase of well over 50% in 2021. In 2019, 75 pitchers threw at least 150 innings.

So, where are the extra innings going to come from in 2021? Most standard relievers are effective for only one or two innings. That means the upper-level, minor-league starters are going to be critical for teams’ successes during the coming season. Pitching prospects with experience above A-ball, as well as those on the 40-man roster with minor-league options remaining, should benefit the most. Today, I'm taking a look at 15 different starting pitching prospects that could thrive in a hybrid relief role in 2021. If they get an opportunity in the role at the big-league level, don’t hesitate to grab them as many of the pitchers could rack up strikeouts and “vulture” wins while providing multiple innings of out the bullpen.

Tier 1

Michael Kopech, RHP, White Sox
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

First the bad news: Kopech hasn’t pitched in two years. Now the good news: His stuff still looks strong after Tommy John surgery and sitting out the pandemic-shortened season. Kopech might be better served by receiving regular innings at the alternate training site (or triple-A) but when he last pitched he also struck out 170 batters in 126.1 innings at triple-A so he’s probably ready for a relief role in the majors. His control remains a work-in-progress but he has the raw stuff to overpower big-league hitters once or twice through a lineup.

A.J. Puk, LHP, Athletics
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

Puk arguably has the best overall stuff of any pitcher on this list but he comes with serious health concerns. He’s thrown just 36.2 innings since 2017 due to Tommy John surgery and a shoulder strain. Because of these concerns, Puk’s best role might be as a reliever that only throws two or three innings in each appearance. But during that limited stretch, his four-pitch repertoire would be more than capable of dominating big-league hitters and racking up strikeouts.

Shane McClanahan, LHP, Rays
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB (playoffs)

McClanahan was the 31st-overall selection in the 2018 draft out of college. He’s a hard-throwing lefty with a history of control issues but he made huge improvements in that area in the second half of 2019. He even made his MLB debut last season in the playoffs and pitched two games out of the bullpen. What team couldn’t use a lefty coming out of the bullpen that can hit triple digits and generate empty swings on a breaking ball?

Jhoan Duran, RHP, Twins
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: AA

Duran doesn’t get enough attention for his stuff. He’s now able to get his heater up into triple digits and he backs it up with an outstanding splitter. What Duran lacks are a reliable third offering and consistent command. Even though he has just 37 innings of experience above A-ball, the 23-year-old hurler could dominate in shorter two- or three-inning stretches for the Twins.   

Brailyn Marquez, LHP, Cubs
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

Just 22-years-old and with a heater that can hit 100-102 mph, Marquez has long-term starter potential for the Cubs. But his command and control don’t appear quite ready for big league hitters over a five- or six-inning stretch. A 2021 role out of the bullpen could allow Marquez to gain valuable experience against big-league hitters but limit his exposure to two or three innings at a time. He’s also working to improve his two breaking balls with the slider showing the most potential.

Tier 2

Ryan Weathers, LHP, Padres
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB (Playoffs)

The Padres’ first-round selection in the 2018 draft, Weathers has the makings of a mid-rotation starter but the club also has some of the best starting pitching depth in baseball. That could push him into the bullpen in 2021 — a role he briefly held last year in the MLB playoffs. His fastball has seen a jump in velocity over the past year and it can now touch 97-98 mph. He backs it up with an above-average slider and average changeup.

Hunter Greene, RHP, Reds
On 40-man: No
Minor League Options: Yes
Top Level of Experience: low-A

Greene has the least amount of experience on this list with just 72.2 pro innings and he’s missed more than two years due to Tommy John surgery and the pandemic. However, he looked good coming back from surgery while at the Reds’ alternate training site in 2020 and he’s been up to 103 mph with his fastball this spring. He’s also shown promise with three secondary offerings and his easy delivery hints at future above-average command.

Tucker Davidson, LHP, Braves
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

Inconsistent command/control has hindered Davidson as a starter but it could be less of a concern if he's kept to two- or three-inning stretches. The southpaw’s fastball velocity has increased recently and it now gets up to 97 mph at times. He also has two breaking balls that flash average-or-better. In his last taste of minor-league action, he struck out 122 batters in 110.2 innings at double-A.

Kyle Muller, LHP, Braves
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: AA

Like Davidson above, Muller could thrive in the bullpen for the Braves. A lefty with mid-to-upper-90s heat, Muller’s secondary offerings are still works-in-progress and he struggles to throw consistent strikes. Muller allows his fair share of fly balls but he’s always done a nice job of keeping the ball in the park and has never allowed more than five home runs in a season.

Bryan Abreu, RHP, Astros
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

Abreu could challenge A.J. Puk for the best overall stuff on this list but his below-average command/control keeps him from realizing his full potential. He has two plus breaking balls and a fastball that can work into the upper-90s although he was out of shape in 2020 and lost velocity. If Abreu is motivated, he could be an absolute beast in two- or three-inning stretches for the pitching-needy Astros in 2021.

Tier 3

J.B. Bukauskas, RHP, Diamondbacks
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: AA

Bukauskas is a former first-round pick of the Houston Astros but his command and control struggles have slowed his development. Now with the Arizona Diamondbacks, the right-hander has been treading water and during his last competitive action in 2019 he struck out 98 batters in 85.2 innings but also walked 54. Bukauskas needs to trust his stuff and pitching in shorter stints could allow him to focus on throwing strikes with his mid-90s heater and plus changeup.

Seth Romero, LHP, Nationals
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

A former first-round pick, Romero has battled through injuries and has significant maturity concerns but performed well enough at the alternate training site in 2020 to earn a brief MLB trial. The left has a low-90s fastball and could miss bats with his two above-average secondary offerings (slider and changeup).

Luis Medina, RHP, Yankees
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: A+

It’s been a tough road through the lower minors for Medina despite being able to hit triple digits with ease. Back in 2019, the right-hander walked 67 batters and threw 26 wild pitches in 93 innings in low-A ball. But he made some improvements at the alternate training site in 2020 and threw significantly more strikes in winter ball. Medina will likely never have better-than-average command and control but his plus heater and promising secondaries could make him a powerful weapon out of the bullpen.

Chris Rodriguez, RHP, Angels
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: A+

Selected out of high school in the fourth round of the amateur draft back in 2016, Rodriguez has thrown less than 80 pro innings due to a serious back injury that was repaired through surgery and, of course, the pandemic. He can reach the upper 90s with his heater and he has a chance at four average-or-better offerings but the Angels may wish to limit the wear-and-tear on his back by easing him into the Majors as a multiple-inning reliever.

T.J. Zeuch, RHP, Blue Jays
On 40-man: Yes
Minor League Options: Yes
Top Level of Experience: MLB

Zeuch doesn’t have the same swing-and-miss stuff as the other pitchers on this list but he has a bowling-ball-like fastball that is almost impossible to put in the air. There is value in fantasy baseball in having a pitcher that can throw a bunch of scoreless innings out of the bullpen, strike out the odd hitter, and keep the ball in the park. With improved infield defense this year, the Jays are better suited for a pitcher of Zeuch’s talents than in the past. He has the most value in leagues that punish pitchers for allowing home runs.

Download Our Free News & Alerts Mobile App

Like what you see? Download our updated fantasy baseball app for iPhone and Android with 24x7 player news, injury alerts, sleepers, prospects & more. All free!

More Fantasy Baseball Advice