Cardinals general manager John Mozeliak announced the news Sunday. Walden made his last appearance April 29 before going on the disabled list with right biceps inflammation.
Walden was acquired in a trade from the Atlanta Braves last November and shortly after signed a two-year, $6.6 million deal with St. Louis.
Surgery to repair his right rotator cuff remains a possibility for Walden. If Walden decides against surgery, he faces a ''rigorous'' rehabilitation to build strength around his rotator cuff that would allow him to pitch next season. Walden has spent the past four months rehabbing the injury.
Walden made 10 appearances in April with a 0.87 ERA.