NEW YORK -- Cincinnati Reds prospect Montrell Marshall, the MVP of last month's Midwest League All-Star Game, was suspended 50 games without pay on Saturday for violating the Minor League Drug Prevention and Treatment Program.
The Office of the Commissioner of Baseball announced that Marshall tested positive for a drug of abuse for the second time.
Minnesota Twins infielder Sean Miller also received a 50-game ban after a second positive test for a drug of abuse.
Marshall was named All-Star MVP after he hit a walk-off single in the 10th inning to give the Eastern Division a 3-2 victory. He's batting .186 with two homers and 22 RBIs Class A Dayton, striking out 89 times in 226 at-bats.
Video: Midwest East's Marshall knocks in game-winner
A 2014 12th-round Draft pick, the 22-year-old spent the last two seasons with Rookie-level Billings.
2018 Minor League suspensions
Miller has spent the bulk of his time this season with Double-A Chattanooga but went 3-for-33 (.091) during a 10-game stint with Triple-A Rochester in May. The 2015 10th-round pick is batting .220 with a .551 OPS, one homer and eight RBIs in 46 games with the Lookouts.
As a member of Class A Advanced Fort Myers last season, Miller was part of the franchise's first triple play.
Marshall is the third Reds prospect to receive a suspension this season, while Miller is the first player in the Twins system to be banned.