Lohse was injured running to first base on a single during Friday night's game against the San Diego Padres.
Lohse left the game immediately and was the loser as the Cardinals dropped a 4-0 decision.
Right-handed pitcher Mitchell Boggs was recalled from Triple-A Memphis to replace Lohse on the St. Louis roster.
Lohse went on the disabled list for the second time this season after never having been on the DL in his eight-year career before. He was out from June 4-July 11 with a strained right forearm flexor.
Lohse is 5-8 with a 4.67 ERA in 18 starts.