ST. LOUIS -- The makeup of the Cardinals is ever-changing this year, and Friday was just the beginning of another chapter in that saga.

In an expected move, the Cardinals activated left-handed pitcher Randy Flores from the disabled list and recalled right-hander Kelvin Jimenez from Triple-A Memphis. To make room on the roster, the Cardinals optioned both reliever Chris Perez and outfielder Joe Mather to Memphis.

Flores and Jimenez add a great deal of depth to a bullpen that faltered toward the All-Star break. Flores gives the Cardinals a second left-handed option out of the bullpen and Jimenez provides great stuff, though he just hasn't been able to put it all together at the big league level.

It is the third time Jimenez has been called up to pitch in the Majors this season.

"My guess is [Jimenez] probably comes here and tries to do a little too much," manager Tony La Russa said. "When the report comes back, they're raving about how he's throwing. It's just realizing what he's got."

Flores, on the other hand, has been a mainstay in the Cardinals bullpen for the past five years and was glad to be back.

"It was good," Flores said of the time off. "It was just a matter of getting some inflammation and irritation down. Once that was taken care of, it was all about getting work in."

While Flores and Jimenez get to pitch again for the Cardinals, Mather and Perez were sent down with a list detailing what parts of their game needed work.

Perez, who did not allow a run in his first seven starts for the Cardinals, struggled of late in multiple-inning situations. In his final 10 appearances, Perez struck out 13 batters in 12 1/3 innings, but posted a 6.57 ERA.

After demoting Mather, the Cardinals have 13 pitchers on the roster for the first time since Interleague Play.

"We sent Chris down so he can just keep working on his arsenal," La Russa said. "Jimenez has been throwing the ball real well, and we're going to be playing a bunch of games in a row. We're going to have that extra pitcher, that extra player."