In addition, the club placed left-hander Kevin Siegrist on the 10-day disabled list with left forearm tendinitis.
Wainwright, 35, is making his 21st start of the season and ranks among National League leaders in wins with 11. He needs just five strikeouts to reach the 100 strikeout plateau for the eighth time in his career, second-most in Cardinals history behind Bob Gibson (14).
Wainwright (11-5, 4.79 ERA) was placed on the 10-day disabled list on July 25 (retroactive to July 23) due to mid-back tightness and missed 13 games. It marked just the fourth time in his career to land on the DL list.
Siegrist, 28, has made 39 relief appearances for St. Louis this season, going 1-1 with a 4.98 ERA in 34 1/3 innings. He spent time on the disabled list earlier this year (June 23-July 13) with a cervical spine sprain.