DeJong was the only Cardinals player to have appeared in all 41 games this season, and he is hitting .260 with eight home runs and 19 RBIs.
Reliever Matt Bowman also was placed on the disabled list with multiple blisters on his pitching hand, raising St. Louis' total to seven players placed on the DL over the past 10 days. Bowman is 0-1 with a 5.82 ERA in 17 appearances.
St. Louis called up infielder Yairo Munoz and outfielder Tyler O'Neill from Triple-A Memphis to fill the roster spots of DeJong and Bowman. Munoz played in 11 games earlier this season for the Cardinals, and O'Neill is hitting .319 with 13 home runs and 31 RBIs for Memphis.
The Associated Press contributed to this report.