Many of the big stories in the Chicago Cubs minor league system so far in 2026 have been among the position players, but a handful of pitching prospects have taken a step up in development, including right-handed starter Mason McGwire. The son of Mark McGwire, Mason was drafted out of high school back in 2022, and although it took a few years to get going, the pitcher is now breaking out this season, making a name for himself.
Earlier this week, MLB revealed the rosters for the 2026 Futures All-Star Game, and the 22-year-old pitcher was selected to the National League team. McGwire began the minor league season at Low-A Ball with the Myrtle Beach Pelicans, and after a dominant showing, he was promoted to the Midwest League with the South Bend Cubs at the end of May.
McGwire pitched three innings on Wednesday, striking out a pair while allowing one run.
Overall, this year, McGwire has a 3.00 ERA in 48 innings with 64 strikeouts. Since his promotion to South Bend, McGwire has struggled with his control, walking nine batters and hitting two batters in 18 innings. The strikeouts are still there, at 24.4 K%, but he’ll definitely have to get the wildness under control to continue his rise in the Cubs farm system.
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Baseball American recently updated its prospect rankings and McGwire was one of a few risers listed for the Cubs.
McGwire will be joined by switch-hitting outfield prospect Josiah Hartshorn, who will also represent the Cubs in the Futures All-Star Game. Hartshorn, only 19 years old, has already climbed to the No. 1 spot in the Cubs’ farm system, according to Baseball America.
Mason McGwire Promoted to South Bend
This is certainly a guy Chicago Cubs fans should take notice of, as right-handed pitching prospect Mason McGwire has been promoted to South Bend. The right-handed starter has come out of nowhere in 2026 and has quickly established himself as one of the organization’s new star pitching prospects.
The son of MLB slugger Mark McGwire, Mason is making a name for himself in the Cubs’ minor league system. It took some time for the pitcher to get going after he was drafted in 2022, but the stuff looks legit, and now the Cubs want to see him at the next level in High-A Ball.
The 22-year-old has pitched in 10 games down in Myrtle Beach so far this season, including five starts. It may only be a 30-inning sample size, but McGwire is racking up the strikeouts, so a new challenge will be thrown his way.
It’ll be interesting to see how aggressive the Cubs will be with McGwire this season. At 22-years-old, he’s a bit behind at High-A Ball, but if he truly has figured it out and has everything clicking, then it wouldn’t be surprising if he’s at the doorstep of the majors by the end of this season.
Taken in the eighth round of the 2022 MLB Draft, McGwire is eligible for the Rule 5 Draft after the end of this year. So, if the Cubs want to protect him from getting plucked away from another team, he’ll have to get added to the 40-man roster once the 2026-27 offseason kicks off.
McGwire may get fast-tracked through multiple levels in the minor leagues this year, so the team can see just how much he has developed and if there’s a chance he could become a potential piece as soon as next year.
