The Cardinals have shut down Troy Glaus from his Minor League rehab assignment because the bulging disk in his lower back has not responded to treatment, according to The Associated Press.
The third baseman had arthroscopic surgery on his right shoulder in January. He has not played all season.
Glaus was examined by team doctors in St. Louis last weekend and the club said it will be a week to 10 days before he's able to resume baseball activities, according to the report. Glaus left a rehab game with Double-A Springfield on July 27 after one at-bat because of his ailing back.
"He wouldn't do that unless there was some issues," manager Tony La Russa told the AP before the Cardinals faced the Mets on Tuesday.
La Russa said Glaus may be able to return to the big leagues in September. The slugger hit .270 with 27 home runs and 99 RBIs last season.
In his absence, the Cardinals have used six players at third base. Mark DeRosa was acquired from Cleveland in June to help anchor the position.
Additionally, the Cardinals were without shortstop Brendan Ryan for the first game of the two-game set at New York because of Ryan's bruised left ankle, the report said.
"Realistically, if [Ryan] could get back Friday, that would be great," La Russa said. "We'll see."
Jesse Sanchez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.