Wainwright's DL trip is retroactive to Sunday as he is experiencing mid-back tightness. Fowler is out with a strained left wrist.
The team did not immediately announce a corresponding move for Wainwright, but has called up prized outfield prospect Harrison Bader to take Fowler's spot.
Bader, who is the sixth-ranked prospect in the Cardinals' minor league system according to MLB.com, is hitting .297 with 19 homers and 48 RBIs in 97 games at Triple-A Memphis.
It is unknown how long Fowler will be sidelined.
Fowler is hitting .241 with 14 home runs and 37 RBIs this season, his first with St. Louis. Wainwright leads the Cardinals with 11 wins despite a 4.89 ERA that is his career worst since becoming a starter in 2007.