Tigers promote prospects John Peck and Brett Callahan to Toledo

Detroit sent John Peck and Brett Callahan from Double-A Erie to Triple-A Toledo, putting the Tigers’ No. 13 and No. 28 prospects on the doorstep of the big leagues and into the level where their bats and gloves will be judged against older, sharper pitching. Peck, a 23-year-old shortstop taken in the seventh round of the 2023 draft out of Pepperdine, and Callahan, a 24-year-old outfielder drafted in the 13th round out of St. Joseph’s, were both promoted into the club’s top minor-league affiliate with more movement expected around this point in the season.

For Peck, the jump to Toledo is the next test of whether his production can keep climbing once pitchers have a clearer book on him. He has hit .285/.328/.511 with 10 home runs and 19 stolen bases, numbers that show impact from the left side and enough athleticism to stay in motion on the bases. MLB.com had already tracked his rise through the system after he hit .301/.359/.433 with 27 doubles, 11 homers, 69 RBIs and 19 steals across High-A West Michigan and Erie before the midseason promotion. He also picked up weekly prospect honors in early May, further cementing his place among the Tigers’ most watched minor leaguers.

Callahan arrives in Toledo with a different calling card. The left-handed hitter opened 2026 in Double-A with positive results after showing real raw power in spring training, including two Grapefruit League homers hit above 105 mph and another ball that left the bat at 112.2 mph. In Erie, he hit .268/.374/.504 with 12 home runs and 20 stolen bases, a line that gives the Tigers a clearer look at whether his power can translate when the pitching tightens and the margin for error shrinks.

The promotion also keeps the two prospects on the same path after they had been contributing together in Erie, including games where Callahan homered and Peck drove him in. Now the assignment changes. Toledo is not just a reward for good Double-A numbers, it is Detroit’s last major checkpoint before roster decisions start to harden, and both players have to show plate discipline, power translation, defensive versatility and enough fit for a future role to turn prospect status into real MLB depth value.