Glaus had arthroscopic shoulder surgery in January and hasn't played all season. The Cardinals have used six players at third with Glaus out and acquired Mark DeRosa from Cleveland in June to help anchor the position for the rest of the year.
Glaus was examined by team doctors in St. Louis over the weekend and the club said it will be a week to 10 days before he's able to resume baseball activities. He left a rehab game with Double-A Springfield on July 27 after one at-bat because his back was bothering him.
"He wouldn't do that unless there was some issues," manager Tony La Russa said before the Cardinals beat the New York Mets 12-7 in 10 innings on Tuesday night.
La Russa said Glaus may be able to return to the majors in September. He batted .270 with 27 homers and 99 RBIs last year while primarily batting fifth.
The Cardinals also were without shortstop Brendan Ryan for the opener of a two-game set at New York. Ryan hasn't played since he bruised his left ankle on a foul ball in the Cardinals' 5-3 loss Thursday night to the Dodgers, but took batting practice before the game against the Mets.
St. Louis and New York play again Wednesday afternoon and the Cardinals are off Thursday before opening a three-game series at Pittsburgh on Friday.
"Realistically if he could get back Friday that would be great," La Russa said. "We'll see."
Julio Lugo got the start at shortstop with Ryan out. Ryan is batting .281 with one homer and 17 RBIs in 81 games this season.