HOUSTON -- Jeff Keppinger ran in the outfield prior to Thursday's game, hoping his ailing left big toe would respond well enough so he wouldn't have to go on the shelf. Keppinger continued to have pain, forcing the Astros to place him on the 15-day disabled list following Thursday's game.

The Astros purchased the contract of infielder Anderson Hernandez.

"I did some baseball activities earlier today and it wasn't where we'd hoped it would be, so we thought it would be in the best interest to let it calm down," Keppinger said. "It's basically swelling around the little bone in there that's surrounded by tendons and stuff, and I just irritated something. It's a matter of letting it calm down."

Keppinger is hitting .285 with five homers and 46 RBIs this year and leads the club in multihit games and doubles. Geoff Blum made his third consecutive start at second base Thursday in place of Keppinger, but don't be surprised to see Hernandez or Angel Sanchez get some time at second.

"It's going to be tough to get Blummer in there all the time," manager Brad Mills said. "We don't want to kill this guy, either. He'll do a great job for us, but to put him out there every day might be asking an awful lot. We'll wait to see what happens and go from there."

Manzella returns after tinkering swing

HOUSTON -- Bleary-eyed from an early-morning flight to Houston from Portland, Ore., shortstop Tommy Manzella rejoined the Astros on Thursday afternoon and was activated for the first time since he fractured his left index finger in a game June 22.

Manzella, who hit .366 in 11 games during a Minor League rehab assignment between Double-A Corpus Christi and Triple-A Round Rock, was the Astros' starting shortstop for the first half of the season and hit .212 with five doubles, a homer and 16 RBIs before being injured while diving for a ball.

"It's been a little bit longer than I thought it was going to be," Manzella said. "It took me six weeks to get cleared and I was hoping it didn't take that long. A lot of the adjustments I was going to make, I was able to work on them a lot and have an extended period to do it. It was definitely beneficial and I'm just going to take the positives out of it."

Manzella worked with hitting coach Jeff Bagwell on a few adjustments to his swing before he went out on his rehab assignment, and the rookie shortstop was eager to implement some of those things in a Major League game.

"I'm interested to see how that's going to translate here and I'm definitely ready to go," he said. "I'm at the 200 at-bat point, and I was just starting to understand the adjustments I needed to make. I hopefully can just keep building off that, where I can almost try to pick up right where I felt I was starting to get before I got hurt."

Manzella's return makes shortstop crowded

HOUSTON -- The return of Tommy Manzella means he will be splitting time at shortstop with Angel Sanchez, who has played well in Manzella's absence. Astros manager Brad Mills hinted that Sanchez will get most of the playing time, but he definitely wants to work Manzella in.

"I think Angel has earned a shot to play there a little bit," Mills said. "Tommy's going to play some. Do I know exactly how much? I haven't looked at all the pitching matchups yet to see, and that's going to have a lot to do with it as well. We'll kind of see how that goes forward."

Sanchez, acquired in a trade with Boston in July, has played well this year. He entered Thursday hitting .291 with 16 RBIs in 36 games, but isn't as polished defensively as Manzella.

"Obviously, Angel had done a tremendous job for us playing on a daily basis and he has earned the opportunity to play a lot out there. But at the same time, Tommy will get his opportunities," general manager Ed Wade said.

Mills said he's talked to Sanchez about possibly playing second base and he was open to the idea. He even didn't rule out Manzella getting some reps at second base at some point.

"We're probably going to talk to him about playing some second," Mills said.

Moehler's simulated game goes well

HOUSTON -- Right-hander Brian Moehler, who has been on the disabled list since July 8 with a right groin strain, threw about 50 pitches during a simulated game Thursday afternoon, when he threw three innings and impressed manager Brad Mills.

"I don't know if he was starting to feel more comfortable or got used to it, but I thought his stuff got better as he went along," Mills said. "He started gaining more confidence in his leg and his groin and had more hop on his fastball and more sink."

Moehler aggravated his groin injury two weeks ago in St. Louis while throwing a simulated game, tearing the tendon off the bone. He opted to not have surgery with hopes of returning to the mound this year. He'll throw a bullpen session Saturday or Sunday, and if all goes well, will be sent out on a Minor League rehab.

"I felt pretty good and I'll just take it from there," said Moehler, who is 1-4 with a 4.92 ERA in 20 games (eight starts) this year. "I will be more encouraged when I see how I feel tomorrow."