Wacha was scheduled to pitch the Cardinals' series opener at the Washington Nationals on Monday night.
Wacha is 1-0 with a 4.64 ERA in four appearances this season. He last pitched April 17, then went on the IL two days later.
The Cardinals made room on the roster for Wacha by optioning rookie righty Ryan Helsley to Triple-A Memphis.
Helsley made his major league debut April 16 and pitched in relief three times, with a 2.84 ERA across 6 1/3 innings.