PITTSBURGH -- Yadier Molina might be back in the St. Louis Cardinals' lineup by the end of week, much sooner than originally expected.

The star catcher is scheduled to report to Double-A Springfield on Tuesday to work out with the farm club. If all goes well, he will begin a rehab assignment Wednesday night against Arkansas in a Texas League game.

When Molina tore ligaments in his right thumb July 9 and had surgery two days later, it was expected that he would be out until mid-September. Instead, his rehab has gone without a hitch, and he could return to the Cardinals as soon as Friday night when they open a four-game home series against the Chicago Cubs.

"I hate to put timetables on injuries, but if he is medically cleared, then it's a possibility," Cardinals manager Mike Matheny said of getting Molina by the weekend. "We have to make sure he feels comfortable swinging a bat and throwing before that decision can be made."

Molina is hitting .287 with seven home runs in 87 games this season. He was selected to his sixth consecutive All-Star Game, though he was unable to play because of the injury. He has also won six National League Gold Gloves in a row.

Veteran A.J. Pierzynski is doing the bulk of the catching with Molina sidelined. Signed by the Cardinals on July 26 after he was released 10 days earlier by the Boston Red Sox, Pierzynski is hitting .277 with one homer in 19 games with St. Louis.