SALVO, North Carolina (Reuters) - Jamaican world 100 metres record holder Asafa Powell has strained a pectoral muscle, but the chest injury is not expected to seriously affect his Olympic preparations, his manager said on Sunday.

"It's not a big deal," Paul Doyle told Reuters via telephone after Powell pulled out of a scheduled relay appearance at the Mount San Antonio College Relays in Walnut, California because of the injury.

"He had a problem in the weight room and he hurt his chest bench-pressing," Doyle said of the injury, which occurred last week in Jamaica.

"He can't reach back to receive the baton," Doyle said. "His arm is restricted in going back.

"He is fine walking around, but he can't aggressively drive his arms. He probably could have run today, but it probably would have been a little painful."

Although Doyle said the injury was not major, he said Powell had flown to Portland, Oregon, to see a specialist.

"He should be fine for the Penn Relays (in Philadelphia on Saturday) and also for Doha," Doyle said.

Powell is scheduled to run another relay at Philadelphia, then relaunch his 100 metres season at a May 9 meeting in Doha. He ran 10.04 seconds in Australia in February. His world record is 9.74 seconds.

Powell's chief rival for the 100 metres title in Beijing, American world champion Tyson Gay, ran in the California meeting.

"I felt pretty good," Gay said after anchoring his team to a winning time of 38.51 seconds, the fastest this year.

"Once I got running, my legs were good. I feel really good. Everything went well. It was smooth, back to normal."

(Additional reporting by Danny Moloshok in Walnut, California; Editing by Greg Stutchbury)