Pena underwent surgery Thursday to repair his fractured left ankle, Adam McCalvy of MLB.com reports.
Pena suffered the unfortunate injury while stealing a base in a game with Double-A Biloxi earlier this month. Though the Brewers didn't disclose a timetable for Pena's rehab, it's the type of procedure that typically carries a 6-to-9 month absence. That puts the top prospect's status for the start of the 2027 season in limbo. Pena -- who turns 20 in November -- slashed .296/.380/.415 with three home runs, 35 stolen bases and a 30:58 BB:K over 70 games this season, with 51 of those contests coming at High-A Wisconsin.