The Cardinals also announced before Tuesday night's game at Milwaukee that infielder Brian Barden and outfielder Nick Stavinoha are being recalled from Triple-A Memphis. St. Louis is sending infielder Tyler Greene to Memphis.
DeRosa, acquired last month from the Cleveland Indians, was injured during a June 30 game. He got off to a stuttering start with the Cardinals, going 0 for 9 in three games after batting .270 with 13 homers and 50 RBIs with Cleveland.
Barden batted .238 with four home runs and 10 RBIs in 51 games for the Cardinals this season, earning top NL rookie honors in April. Stavinoha batted .234 with one homer and 13 RBIs in 27 games with St. Louis this season.
Ouch! Already, not a good sign for the Cardinals.