HOUSTON — Before Monday’s 7-3 loss to the Astros, the one thing about A’s starter Jesse Chavez that was consistent through good times and bad was his ability to keep the ball in the park.

He came into Houston having allowed just one homer in his last eight starts, and he’d never allowed more than two homers in a game in his big league career. Monday he allowed three home runs to the Astros, who are nobody’s idea of murderer’s row.

The Astros finished with four homers on the night as for the third time in three series Oakland dropped the first game of the set. The last two times, against the Astros in Oakland and against the Rangers in Arlington, Texas, the A’s had come back to win the next two games and the series, but it’s not easy to win after getting in a hole time after time.

For the moment, however, the A’s have bigger concerns. They lost center fielder Craig Gentry to a broken right hand Monday when an MRI revealed what a Sunday X-ray didn’t, a nondisplaced fracture near the wrist.

The A’s are hoping that Gentry will miss just a couple of weeks. But with the club’s other center fielder, Coco Crisp, having an MRI of his own late Monday in the Bay Area because of a neck problem, Oakland is having its depth tested. Oakland called up Billy Burns from Double-A Midland to fill in for Gentry, although for now Yoenis Cespedes will get most of the starts in center with Brandon Moss taking over in left.

“I did the same thing last year when Jarrod Parker hit me on the left hand,” Gentry said. He was playing for the Texas Rangers at the time. “I only missed two weeks then, and I’m hoping that’s the case again this time.”

Manager Bob Melvin concurred with the two-week timetable, although he also said he was looking at the bright side.

“It was disappointing news,” Melvin said. “We know it’s going to be two weeks, and hopefully that’s it. It’s a blow, but we’re going to have to get past it. We’re optimistic that’s it, but you never really know.”

Chavez had allowed only two homers twice this season, and he hadn’t done it at all since May 18. But former A’s slugger Chris Carter crushed him with a three-run homer in the third inning to wipe out an early 2-0 Oakland lead. The A’s came back to tie the game at 3-all on Cespedes’ sacrifice fly in the fifth.

That’s where things stood when Chavez walked Carter with one out in the sixth. Jason Castro unloaded with his 10th homer, and the local fans had scarcely gotten back into their seats after celebrating a 5-3 lead when Marc Krauss homered, too.

Chavez was done, but the Astros were not. With Dan Otero in to try to close out the inning, Matt Dominguez hit the third Houston homer of the inning.