HOUSTON — The Houston Astros turned to the long ball after their starting pitcher went down with an injury.

Carlos Lee and Lance Berkman homered for the second straight game and the Astros hit a season-high four home runs in a 6-3 win over the Pittsburgh Pirates on Wednesday night.

Jeff Keppinger and Hunter Pence added solo shots for the Astros, who came in with a major-league low 50 homers this season.

"They always say they come in bunches, so we'll take 'em," Berkman said. "We've had a dearth of them to this point in the season. Any time you can get four or five home runs in a game, we'll take it."

Casey Daigle (1-1) pitched two scoreless innings in relief to earn his first victory since May 2004. Astros starter Brian Moehler left after three innings with a strained right groin.

Moehler said the injury was minor, and he'll take advantage of the upcoming All-Star break to heal carefully.

"It's nothing I'm overly concerned about," Moehler said. "It couldn't have come at a better time, with four days off and then four days after that."

Berkman has homered in three straight games, the first time he's accomplished that feat since he hit homers in four consecutive games between July 29-Aug. 2, 2007.

The slugger had arthroscopic surgery on his left knee in March and said he finally feels like it's back at full strength, helping him drive balls farther.

"I've really felt comfortable all year," he said. "I think getting a little stronger on my back leg, I'm able to stay on my back side a little bit longer and that certainly helps. Other than that, you get to a certain point in the season, at some point, you've got to make a little bit of a run and hopefully, I'm starting that."

Pirates starter Daniel McCutchen (1-4) allowed three of Houston's four homers in five innings of work. McCutchen was optioned to Triple-A Indianapolis after the game, the corresponding roster move after the Pirates acquired right-handed reliever Sean Gallagher.

"The few times I needed to execute a pitch, I didn't," McCutchen said. "Overall, in the big situations, they scored three runs with two outs and hit the home run. Oh well."

Keppinger extended his hitting streak to nine games with a solo homer in the first.

Berkman drew a two-out walk in the Astros' half of the third, and Lee followed with a homer to left, his 12th. Lee went 19 games and 71 at-bats without a home run before hitting a solo shot in Tuesday's 6-2 victory.

Left-hander Gustavo Chacin replaced Moehler for the fourth and Garrett Jones led off with a double. Pedro Alvarez walked before Ryan Doumit drove in Jones with a single to right to make it 3-1.

Ryan Church tied it with a double to the gap in left center.