Bobby Crosby, the only Athletic to start all 84 games this season, strained his left hamstring while beating out an infield single in the eighth inning of the Angels' 7-4 victory in the finale of a three-game series at Angel Stadium and was immediately removed from the game.
"It was kind of bugging me the whole game," Crosby said. "In the second and third inning it was a little tight, and then it died down. And then I'd have to run, and it fired up again, and then it died down again."
It fired up again in a big way as Crosby legged out his eighth-inning dribbler.
"I'm hoping it kind of dies down again," he said.
Crosby told A's manager Bob Geren that his hamstring still was "pretty painful" after the game, but he was optimistic about being ready to play in the four-game series against the host White Sox that opens Thursday at U.S. Cellular Field.
"I'm confident it's just a strain," Crosby said, adding that an MRI wasn't in the plans. "I know it's nothing major."
At best, it'll serve as a bummer of a footnote on a bummer of a day for the A's, who fell 5 1/2 games behind the division-leading Halos.
Juan Rivera blasted a two-run homer off A's reliever Keith Foulke in the bottom of the sixth inning, Erick Aybar hit a solo shot off Santiago Casilla an inning later, and Chad Gaudin allowed an Angels insurance run in the eighth, underscoring Oakland's recent bullpen woes.
Over the past 16 games, A's relievers are 1-4 with three blown saves with a 5.85 ERA, having allowed 26 earned runs on 45 hits and 12 walks over 40 innings.
"The last couple games, we've had some rough outings," Geren said, referencing a Tuesday loss in which Alan Embree gave up Garret Anderson's tie-breaking two-run homer in the bottom of the eighth. "They'll bounce back."
Pitching for the first time since Saturday and the second time in 11 days, Foulke entered the game with the score tied at 3 and a runner on second with two out. After giving up a tie-breaking double to Casey Kotchman, Foulke surrendered Rivera's first home run of the year, a towering shot into the left-field bleachers.
A's catcher Rob Bowen said the pitch Rivera hit out was a "hanging split," but he, too, expressed confidence in the bullpen's ability to right itself.
"Our bullpen's been solid the whole year," he said. "You can't take too much from [the recent slump]. I expect them to get right back to where they were."
It would certainly help if Casilla would find the form that made him Oakland's most reliable reliever early in the season. Since opening the year with a streak of 17 1/3 scoreless innings, he's been on the disabled list with a sore elbow (May 16-June 10) and has allowed a run in each of his past seven appearances.
"His velocity is good," Geren said. "He just keeps getting victimized by one bad pitch. It might be a confidence thing, coming off the DL not too long ago. Each time out he'll throw better and better."
The Angels opened the scoring on a wild pitch by A's starter Dana Eveland (6-6) in the first inning. The Halos made it 2-0 on an RBI groundout in the second, but the A's scored an unearned run in the fourth and got a two-run single from Mark Ellis to take the lead in the top of the sixth.
After Rivera's homer, the A's closed the gap with another unearned run in the top of the seventh. Aybar's homer was his third.
"You've gotta give the hitter credit every now and then," Bowen said.
"They got the big hits," Geren said.
Eveland gave up three runs on four hits and one walk while striking out four, while Angels starter Joe Saunders gave up six hits over 6 1/3 innings and improved to 12-4.
"It was a good series," Eveland said. "They're a tough team, but we still play them a bunch more times. We play them three times at home next week, so hopefully we can win two or three of those and get the game back we lost here.
"I don't think they're a better team than we are. It's a pretty darned good matchup."
Mychael Urban is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.