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05/12/09 7:24 PM ET

Ryan beginning rehab assignment

Infielder headed to Triple-A to recover from hamstring strain

PITTSBURGH -- Infielder Brendan Ryan was scheduled to begin a Minor League rehabilitation assignment for Triple-A Memphis on Tuesday, but it's not a certainty when that stint will end.

Ryan has been sidelined since April 30 due to a right hamstring strain. He was originally slated to begin his rehab four days earlier, but he wasn't quite 100 percent, so the Cardinals pushed it back until Tuesday. Now he's ready to play, but manager Tony La Russa wants to make sure that Ryan isn't just healthy, but that he's playing at a high level before he's recalled from the Minors.

"I think he needs to make sure he's playing well," La Russa said. "He's still a young player. He wasn't playing a lot here [before he was injured]."

Ryan was, however, playing well before he got hurt. He had been hitting effectively and playing exceptional defense. He is eligible to come off the disabled list on Friday.

Another consideration, when that decision time comes, is that the Cardinals may be ready to cut back to 12 pitchers by Friday. La Russa acknowledged that the club's 13-man pitching staff may be nearing the end of its run.

"Through this series for sure," he said of the arrangement, "and then [we'll] make a judgment for this weekend."

Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.