Pena (knee) underwent surgery Tuesday and is expected to need about a month to recover, MLB.com's Jenifer Langosch reports.

EDGE Analysis

The surgery was to remove a loose piece of cartilage from his left knee, and while the club initially believed it might only be a two-week recovery, the team is now prepared to be without him for the rest of April. He should serve as the Cardinals backup catcher when he rejoins the team in May.