HOUSTON -- Talk about a fun youth movement. The Houston Astros are piling up the wins while they shed some of their most experienced players.
The Astros trailed 2-0 before Michaels' drive to the first row of the Crawford Boxes in left field. It was his seventh homer of the season.
Houston, starting four rookies since Lance Berkman was traded on Saturday, has won five straight games while Milwaukee has dropped its last five. It's the Astros' longest winning streak since a six-game surge in September 2008.
"We just have some guys that want to go out there and play hard," Hunter Pence said. "We're having fun. It's just us now and we've got to look at each other, believe in each other and go out and do it."
Brewers starter Randy Wolf was cruising before he was hit on his left wrist by Pence's single with none out in the seventh, forcing the left-hander out of the game. He was replaced by Kameron Loe (1-2), who walked Carlos Lee and Chris Johnson to load the bases before Zach Braddock took over.
That set up Michaels' second career pinch-hit grand slam.
"It was pretty special to see Wesley throw the ball like he did today," Astros manager Brad Mills said. "It was an absolutely outstanding job to go that far into the game and to pitch as well as he did."
Wolf allowed one run and six hits. X-rays were negative, but Wolf has a bone contusion. He will fly with the team to Chicago before returning to Milwaukee on Monday for more tests.
"Initially that thing hit me really square," Wolf said. "Those are the ones that are scary because they are hard to see. They come at you pretty fast and it got me right on the bone."
Pence was upset about hitting Wolf.
"I hate to see that happen and I hope he's OK," Pence said. "I feel bad. He's a friend of mine. You don't ever want to see anyone take one anywhere."
Wolf was disappointed he had to leave when he was pitching so well.
"That last pitch was my 75th pitch," he said. "Those are the days where you think you can complete the game. But unfortunately, we had some crazy circumstances happen that are out of my control."
Brewers manager Ken Macha didn't like being asked if his team was reeling.
"What kind of a question is that? What do you think? We're happy we lost five in a row?" he said. "We're not happy and we need to start getting some runs on the board. When you only score two runs here, you're not going to win any games here."
Houston stretched the lead to 5-2 in the eighth inning when Pence tripled and scored on an error by second baseman Rickie Weeks. Weeks overthrew third by so much that the ball bounced into the stands behind Milwaukee's dugout.
Corey Hart put the Brewers on top with a two-run homer in the sixth inning. It was his 23rd of the season.
Hart's drive broke a string of 31 straight scoreless innings by Houston's pitching staff. The Astros' streak was tied for second-longest in the majors this season and was the longest such streak by Houston since 1997.
Milwaukee put runners on first and second after Hart's two-out drive, but Wright retired Casey McGehee on a fielder's choice to limit the damage.
Wright didn't allow a hit until Ryan Braun singled to start the fifth inning. He responded by retiring the next three batters.
Wright was excited about his victory and helping extend Houston's winning streak.
"It's big," he said. "We are coming on to the latter part of the season and we haven't quit. That's the big thing. I think people are seeing that no matter what the standings might say, we're going to come in, we're going to play hard and hopefully win some ballgames."
Houston's Brett Wallace got a standing ovation after he singled in the fifth for his first major league hit. It was his second game in the majors after taking over at first base for Berkman, who was traded to the Yankees on Saturday.
Houston reinstated RHP Jeff Fulchino from the 15-day disabled list and optioned LHP Fernando Abad to Triple-A Round Rock after the game. ... The Astros signed RHP Brett Myers to a multiyear contract extension before the game. ... Houston RHP Brian Moehler, who experienced tightness in his strained right hamstring while throwing a simulated game July 23, threw a side session on Sunday. If he feels OK after that, he'll throw a simulated game on Wednesday in St. Louis.