Predicting the 10 September Call-ups Primed to Impact 2022 MLB Pennant Races

Joel ReuterSeptember 2, 2022

Predicting the 10 September Call-ups Primed to Impact 2022 MLB Pennant Races

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    Baltimore's Gunnar Henderson. Nick Cammett/Getty Images

    The annual wave of September call-ups is not what it used to be after roster-expansion limits were trimmed from 40 to 28 during the 2020 season. It allows for a few reinforcements without opening the door for marathon games that feature a dozen pitching changes and countless pauses to the action.

    Despite the smaller number of call-ups, there is still plenty of potential for an impact contributor or two to emerge from this year's promotions.

    Ahead we've highlighted 10 confirmed and speculative September call-ups for contending teams who are primed to impact pennant races.

    It's a mix of top prospects getting their first taste of the majors, young players getting another chance to prove themselves and veterans returning from injury as teams often use roster expansion to activate players from the injured list without having to make a secondary move.

    A few of these players were technically called up before Sept. 1 so they could be added to the 40-man roster in time to be eligible for postseason rosters, but for the sake of this conversation, they are essentially September call-ups.

LHP Matthew Boyd, Seattle Mariners

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    Remember Matthew Boyd?

    He looked like a star on the rise for the Detroit Tigers in 2019 when he racked up 238 strikeouts in 185.1 innings, but he regressed badly during the shortened 2020 season. He rebounded with a 3.89 ERA in 78.2 innings last season before he was sidelined with arm soreness, which eventually led to season-ending flexor tendon surgery.

    After he was non-tendered by the Tigers, the San Francisco Giants signed him to a one-year, $5.2 million deal during the offseason in hopes he could contribute down the stretch, but when they fell out of the race, he was traded to the Seattle Mariners along with backup catcher Curt Casali at the deadline.

    Now he's poised to make his 2022 debut following six relief appearances at Triple-A, and he'll provide a much-needed left-handed option in a bullpen that is made up of eight right-handed relievers.

RHP Hunter Brown, Houston Astros

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    Armed with a high-octane fastball and a devastating hammer curveball, Hunter Brown has emerged as the top prospect in the Houston Astros system and one of the top overall prospects in baseball, checking at No. 47 on B/R's most recent Top 100 list.

    The 24-year-old has posted a 2.55 ERA, 1.09 WHIP and 134 strikeouts in 106 innings at Triple-A Sugar Land, and he has been bouncing between starting and pitching out of the bullpen to prepare for a potential relief role.

    The Astros have already announced that he will be added to the active roster Friday, and he joined the team's taxi squad Tuesday.

    "He has the stuff,” Astros manager Dusty Baker told reporters. “It’s just a matter of, 'Can he command the strike zone?'—which is always the question with young pitchers. How they get the command of their fastball and if they can throw their secondary pitches."

    With Cristian Javier shifting back into the starting rotation after Justin Verlander was placed on the injured list this week because of a calf setback, there is a clear need for a multi-inning reliever in the Houston bullpen.

RHP Jack Flaherty, St. Louis Cardinals

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    The St. Louis Cardinals have built a comfortable lead in the NL Central standings thanks to a strong second half, and they've done it without starter Jack Flaherty.

    The ace of the staff just a few years ago, Flaherty has pitched only 126.2 innings since the start of the 2020 season. That includes just three starts this season, which were sandwiched between a pair of stints on the 60-day injured list.

    The 26-year-old is on the rehab trail from a shoulder setback and set to rejoin the St. Louis staff for the final push. He has made five starts in the upper levels of the minors since returning from his most recent injury, posting a 3.60 ERA with 25 strikeouts in 20 innings, and his final rehab start came on Wednesday at Double-A.

    As long as there are no setbacks, Flaherty is tentatively expected to rejoin the active roster on Labor Day. That could make Dakota Hudson the odd man out in the rotation as he's struggled to a 5.52 ERA with just one quality start since the All-Star break.

SS Gunnar Henderson, Baltimore Orioles

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    The Baltimore Orioles technically called up top prospect Gunnar Henderson on Aug. 31 since he needed to be added to the 40-man roster before Sept. 1 to be eligible for a spot on the potential postseason roster.

    That one bonus game proved fruitful as he went 2-for-4 with a home run in his MLB debut while starting at third base and batting sixth in the lineup.

    The 21-year-old hit .297/.416/.531 with 24 doubles, 19 home runs, 76 RBI, 101 runs scored and 22 steals in 112 games between Double-A and Triple-A this season, and with defensive standout Jorge Mateo penciled in at shortstop, he will likely continue to man the hot corner over the final month of the season.

    "I'm looking forward to being able to sit on the sidelines [or] in the dugout and continue to watch what kind of player he is,” Orioles pitcher Jordan Lyles told reporters. “Tonight, he helped us win a ballgame."

    The future is now in Baltimore.

CF Garrett Mitchell, Milwaukee Brewers

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    It seemed like a coin toss between Garrett Mitchell and Sal Frelick in terms of which promising young outfielder the Milwaukee Brewers would promote in an effort to find a spark offensively.

    That question was answered on Aug. 27 when Mitchell was added to the 40-man roster and promoted to the big leagues, essentially jumping the September call-up window by a few days in order to ensure he would be eligible for the potential playoff roster.

    The No. 20 pick in the 2020 draft, Mitchell hit .287/.377/.426 with 23 extra-base hits and 17 steals in 68 games in the minors this season, and he has started three games since he was promoted, going 2-for-9 with a home run, five RBI and three runs scored.

    It looks like he will be the left-handed-hitting side of a center field platoon with Tyrone Taylor the rest of the way, and the Brewers are in serious need of an offensive boost.

C Gabriel Moreno, Toronto Blue Jays

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    The Toronto Blue Jays gave Gabriel Moreno a brief stint on the MLB roster earlier this year when Danny Jansen was on the injured list, and he went 16-for-58 in 18 games.

    Since returning to Triple-A in mid-July, he's hitting .315/.408/.438 with nine extra-base hits in 103 plate appearances. Calling him back up would allow the Blue Jays to more consistently use Alejandro Kirk in the DH role without leaving catcher exposed should Jansen suffer an injury.

    Moreno, 22, is one of the top prospects in baseball and the catcher of the future in Toronto, but he has seen a significant downturn in his power production this year.

    After posting a .626 slugging percentage in the minors in 2021, he is slugging just .418 at Triple-A this season, and 15 of his 16 hits in the majors were singles. Still, he can be a useful piece of the puzzle as Toronto chases a wild-card berth.

RHP Cody Morris, Cleveland Guardians

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    The Cleveland Guardians know how to develop pitching prospects, and while it's been a winding road to the majors for Cody Morris, he could prove well worth the wait.

    "Although his professional journey has been littered with injuries, his stuff when he’s healthy has been attention-grabbing. His heater can reach 97 mph, and he was dominant when he returned to the mound last year, recording a 1.62 ERA with 93 strikeouts in 61 innings between Double-A and Triple-A," Mandy Bell of wrote.

    Shoulder injuries have been the issue the last two seasons, and he didn't make his 2022 debut until July after suffering a shoulder strain during spring training, but he has a 1.69 ERA with a 39-to-6 strikeout-to-walk ratio in 21.1 innings in the minors pitching mostly in two- or three-inning stints.

    Now he'll join an already solid relief corps, where he has a chance to carve out a late-inning role alongside Trevor Stephan, James Karinchak and Emmanuel Clase.

LHP Kyle Muller, Atlanta Braves

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    The Atlanta Braves' biggest September addition will be a healthy Ozzie Albies once he is cleared to return from a fractured foot. He was slated to begin a rehab assignment Thursday, so we could see him back in the big leagues in the next week or so.

    In the meantime, left-hander Kyle Muller stands as the September call-up most likely to have an impact on the team's stretch run.

    The 24-year-old has struggled to a 5.28 ERA in 11 appearances in the big leagues over the past two seasons, but he has earned another look with strong numbers at Triple-A Gwinnett this year.

    He has a 2.96 ERA, 1.11 WHIP and 139 strikeouts in 118.2 innings, and most importantly he has trimmed his walk rate from 12.2 to 7.4 percent, addressing the biggest issue that has kept him from finding success in the majors. In a multi-inning bullpen role, he could join Tyler Matzek and A.J. Minter as shutdown lefty options.

SS Oswald Peraza, New York Yankees

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    Why have we not seen New York Yankees shortstop prospect Oswald Peraza in the majors yet this season?

    "There hasn’t been a lane yet for, ‘Hey, this opportunity has opened and does he fit this category,” Yankees general manager Brian Cashman told reporters. "The answer hasn’t been a yes for that yet.”

    Incumbent shortstop Isiah Kiner-Falefa has an 81 OPS+ on the season and he's hitting .237/.290/.290 with four extra-base hits in 125 plate appearances since the All-Star break. Is his sure-handed defense worth those offensive shortcomings?

    Peraza, 22, is already on the 40-man roster so it won't take a secondary move to clear a spot for his promotion. With 33 steals in 38 attempts and a 60-grade speed tool, he can fill the pinch-runner role that Tim Locastro occupies on the bench while making one or two starts per week at shortstop. That would provide him an opportunity to prove he deserves more playing time without heaping a ton of immediate pressure on him.

    Here's betting that Cashman will change his tune in the coming days and call him up.

RHP Blake Treinen, Los Angeles Dodgers

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    Veteran Blake Treinen was one of the best relievers in baseball in 2021, posting a 1.99 ERA, 0.98 WHIP and 10.6 K/9 in 72 appearances with seven saves and 32 holds as the team's primary setup man.

    He suffered a shoulder injury in April, and while season-ending surgery was a potential option, he instead opted to rehab in hopes of returning before the season was over.

    That approach appears to have worked as he's nearing a return and is pitching with Triple-A Oklahoma City on a rehab assignment. His fastball touched 98 mph in his last outing, and he has six innings over seven appearances under his belt.

    With Walker Buehler done for the year after Tommy John surgery and both Clayton Kershaw (back) and Tony Gonsolin (forearm) on the injured list, the bullpen could be leaned on more heavily than ever down the stretch, and a healthy Treinen would be a welcome addition.

    All stats courtesy of Baseball Reference and FanGraphs and accurate through Wednesday's games. Prospect tool ratings via


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