St. Louis, MO (SportsNetwork.com) - The St. Louis Cardinals confirmed Monday that ace right-handed pitcher Adam Wainwright will miss the rest of the season with a torn left Achilles, an injury he suffered over the weekend while batting.

Cardinals general manager John Mozeliak held a news conference to announce the results of an MRI and that Wainwright would undergo surgery on Thursday. He is expected to be out of action for 9-12 months.

Wainwright was hurt in the fifth inning of Saturday's game against Milwaukee when he popped up and started to run toward first base.

In four starts this season, the 33-year-old perennial Cy Young contender had a record of 1-2 with a 1.44 ERA.