ARLINGTON -- Darren O'Day was activated from the disabled list after being sidelined since Aug. 25 with inflammation and soreness in his right shoulder. O'Day has been throwing off the mound in the bullpen over the past week and is ready to pitch without physical restrictions in a game.

"He will be used however we feel he needs to be used," Rangers manager Ron Washington said. "He could be used when we're ahead or when we're behind."

But O'Day is not going to move back into his old role as the Rangers' primary right-handed setup reliever. That job has been taken over by Mike Adams and Mark Lowe.

O'Day was 8-3 with a 1.94 ERA in 140 games as a setup reliever over the past two seasons, but has struggled this season. He missed May and June with a torn labrum in his left hip, and he has been up and down from Triple-A since the All-Star break. O'Day is 0-1 with a 5.93 ERA in 13 games.

Cruz activated, but limited to pinch-hitting

ARLINGTON -- The Rangers activated Nelson Cruz off the disabled list on Tuesday, but he is not ready to return to the lineup.

Instead, Cruz is limited to pinch-hitting duty, and he will likely need a pinch-runner for now if he gets on base. When Cruz is ready to return to the lineup, it will likely be as a designated hitter.

"Right now, we're getting him back slowly," Rangers manager Ron Washington said. "We'll use him to pinch-hit and take it a day at a time. We'll probably DH him right out of the chute."

Cruz went on the disabled list on Aug. 29 with a strained left hamstring and was activated on the first day he was eligible. He is still not running 100 percent, though he says he's good enough to play. But Cruz has still not run hard in the outfield.

"The way I run ... when I run, I feel like it doesn't bother me, so I know I'm ready," Cruz said. "Now it's their call. I go day by day -- whatever they decide [about] when I can play, I'll play."

The Rangers want to take it slowly because they need Cruz for the rest of the season and beyond. Like Adrian Beltre, who missed five weeks with a strained hamstring, the Rangers understand that if Cruz re-injures the muscle, he could be sidelined for the rest of the season.

"Today is the 15th day," Washington said. "I'm not a hamstring guy that believes you can come off on the 15th day and be ready. He's available to do what we need him to do, but we're not going to push him on the 15th day."

Prospects Perez, Ramirez join the Rangers

ARLINGTON -- Left-hander Martin Perez and right-hander Neil Ramirez arrived in Arlington on Tuesday. They will be here for two days to work with pitching coach Mike Maddux, hang around the rest of the staff and learn as much as they can.

"It's very important," Perez said. "This is like a present for me with the Rangers. I'm going to take advantage of every single thing, talk to the pitchers, talk to the players, and learn as much as I can and take it to me with Venezuela."

Perez, the No. 1 prospect in the Rangers' system, was 4-4 with a 6.43 ERA in 10 starts at Triple-A Round Rock after going 4-2 with a 3.16 ERA in 16 starts and one relief appearance at Double-A Frisco.

Ramirez, the 44th overall pick in the 2007 draft, began the season at Class A Myrtle Beach, but was jumped to Triple-A after just one start. Ramirez was 4-3 with a 3.68 ERA in 18 starts for Round Rock while striking out 86 in 74 1/3 innings.

He was twice shut down because of shoulder stiffness and made six starts on a rehab assignment at Double-A Frisco, going 1-0 with a 1.89 ERA.

"Structurally, everything has been fine," Ramirez said. "I threw a lot of pitches in a condensed amount of innings. The workload and getting used to everything, like the travel, caught up with me."

Worth noting

• Michael Young was given another hit. An error that was originally charged to A's pitcher Brandon McCarthy on Friday on a grounder back to the mound was changed to a hit for Young.

• Ian Kinsler has been successful on 24 straight steal attempts, breaking his own club record.