HOUSTON -- Wilton Lopez burst into the Astros' clubhouse on Sunday morning, hugging teammates and obviously happy to be back and healthy.

The relief pitcher, who's been on the disabled list since June 11 with a sprained right elbow, rejoined the team following his Minor League rehab stint at Triple-A Oklahoma City, but he won't be activated until the second half of the season gets underway on Friday.

"If he goes through his throwing program today and feels good, we're anticipating activating him after the break," Astros manager Brad Mills said.

Lopez has been a key part of the Astros' bullpen the last few seasons, including this year in going 3-0 with a 2.51 ERA in 32 1/3 innings pitched. Fernando Rodriguez has taken Lopez's role in the bullpen, coming into games with runners on base.

Rodriguez has allowed only four of 25 inherited runners to score, despite a 6.25 ERA.

"Where Fernando has given up runs has been when he has to start an inning or after getting out of an inning and going out for the next inning," Mills said. "He's done such a good job getting out of innings and that's the role we used Lopey, and Lopey's done a good job.

"When we have two of those guys, that's fun for me, because that's another tool to use to help us later in games."

Maxwell expected to replace Dominguez on roster

HOUSTON -- The Astros optioned third baseman Matt Dominguez to Triple-A Oklahoma City following Sunday's game, and manager Brad Mills said outfielder Justin Maxwell would be activated to take his roster spot on Friday if his Minor League rehab progresses as planned.

Maxwell, on the disabled list since June 26 with loose bodies in his left ankle, is on a stint at Oklahoma City, going 0-for-4 while starting in center field on Sunday in New Orleans. He's 2-for-10 in three games

Maxwell, who has eight homers in only 121 at-bats for the Astros, was originally going to have surgery before doctors informed him the procedure was more invasive than previously thought and would require a two-month recovery.

Dominguez, acquired by the Astros on Wednesday from the Marlins in the Carlos Lee trade, appeared in four games and was 2-for-8. Mills said Chris Johnson would slide back to third base after playing first the past four games, which could pave the way for Brett Wallace to be called up and start at first base in the second half.

Shortstop Marwin Gonzalez (bruised right heel) has played in 11 games in his Minor League rehab stint at Oklahoma City, but the Astros are likely to keep him there closer to the 20-game maximum for rehabs.

That gives Gonzalez the opportunity to get some extended playing time at the Triple-A level, which he can't do when healthy, because he's a Rule 5 pick and has to stay on the 25-man roster or disabled list all season. He was hitting .387 (12-for-31) for the RedHawks.

Worth noting

• Astros manager Brad Mills has set his starting rotation for the second half of the season: Wandy Rodriguez, Lucas Harrell and Bud Norris will start in San Francisco, and J.A. Happ and Jordan Lyles will start the first two games of the San Diego series.