ST. LOUIS -- Rick Ankiel can't hit right now, but the Cardinals have decided to keep him on the active roster and hope that his sore right shoulder responds to treatment.

"It's aggravated," manager Tony La Russa said of Ankiel's right shoulder. "He can't swing 100 percent when it's aggravated, so we're going to try to get him well."

The Cardinals had made preliminary plans to bring up outfielder Joe Mather from Triple-A Memphis if club medical officials had decided that Ankiel needed at least 15 days of recovery time, but Cardinals medical supervisor Dr. George Paletta recommended a patient approach. Paletta feels that with treatment, Ankiel might be able to return more quickly than a 15-day DL stint would have allowed.

Because the injury involves Ankiel's non-throwing shoulder, La Russa allowed that Ankiel could conceivably be available to play in the field if needed, but won't be able to take an at-bat until the shoulder comes around. The Cardinals started Skip Schumaker in center field on Sunday against Rays right-hander Edwin Jackson, with Ryan Ludwick in right and Chris Duncan in left.

Ankiel hurt his right shoulder on a swing in his last at-bat on Friday night against the Rays. He had seven game-winning RBIs in the Cardinals' first 24 victories this season.

Retaining Ankiel on the active roster means that Mather will continue to get consistent at-bats for Memphis.

"[Mather] can use the playing time down there, so I'm glad it's not happening," La Russa said.