Henry Sosa got off to a rough start in his first major league game. He eventually settled down and gave Houston a chance.

It might have been enough to earn another turn in the rotation.

Sosa allowed four runs over six innings in the Astros' 6-3 loss to the Arizona Diamondbacks on Wednesday night.

"For the time being we are going to wait and see a few things but he threw the ball well and I have no problem with him getting another start," Astros manager Brad Mills said. "He stepped in and made some adjustments but the stuff is there."

Sosa (0-1) was acquired from San Francisco in the Jeff Keppinger trade on July 19 and had made only one start above Double-A before his contract was purchased on Tuesday.

Willie Bloomquist hit Sosa's fourth pitch over the wall in left, part of a three-run first inning for Arizona, but the right-hander held the Diamondbacks to three hits and one run over his final five innings.

"The first inning I overthrew the ball a little bit," Sosa said. "I wasn't nervous, just happy. It is my first game in the big leagues. I just enjoyed the game."

Sosa struck out four, walked three and hit a batter with a pitch.

"He had to find some things in the first inning," Mills said. "I thought he made some real good adjustments and threw the ball really well after that. I like the way he was able to find himself and come back."

Clint Barmes and Humberto Quintero each had an RBI single for Houston, which has lost five of six. Carlos Lee also drove in a run with a groundout.

The Astros scored twice in the fifth but missed a chance for more. With one out and runners on second and third, Josh Collmenter (7-7) got J.B. Shuck to foul out and retired Jose Altuve on a grounder to third to end the inning and maintain Arizona's 3-2 lead.

Justin Upton double and scored on Chris Young's double in the bottom half, and Arizona added another run in the seventh. Ryan Roberts came home when shortstop Barmes dropped reliever Sergio Escalona's throw to second base on Upton's stolen base.

"We have to keep going out and trying to play good baseball," Upton said.

Gerardo Parra added a run-scoring triple in the eighth, giving the Diamondbacks a 6-3 lead, and David Hernandez pitched the ninth for his 10th save.

Arizona won for the third time in four games and moved a half-game ahead of San Francisco to take sole possession of the NL West lead for the first time since June 24.

Paul Goldschmidt had a two-run single in the first, and Upton finished with three hits.

NOTES: Escalona rushed his throw on Upton's stolen base in part because Barmes was late covering the bag. ... Sosa became the fifth Astros pitcher and ninth Houston player to make his season debut this year. ... Houston RHP Brett Myers enters Thursday's start against Arizona looking to end a career-long six-game losing streak spanning his past eight starts. Myers is 2-2 in 10 appearances and nine starts against Arizona but hasn't beaten the Diamondbacks since June 4, 2005. ... LHP Joe Saunders, Arizona's starter on Thursday, is 8-4 with a 2.76 ERA in his past 15 starts. Opponents have scored 17 of their 63 runs against Saunders in the first inning and are batting .344 in the opening frame.