HOUSTON -- Needing a durable arm to help sustain them during their span of 20 consecutive games, the Giants purchased the contract of right-hander Matt Palmer from Triple-A Fresno on Thursday and optioned left-hander Geno Espineli to Fresno.

Palmer started 24 games for Fresno, posting a 6-9 record with a 4.13 ERA. Manager Bruce Bochy explained that Palmer's ability to pitch multiple innings in relief should prove handy while the Giants play without a rest until Aug. 28.

The unfortunate side effect involved Espineli's fate. Named to Team USA's pitching staff for the Olympics, he was removed from the roster when the Giants promoted him July 20. Espineli declared that pitching in the Major Leagues was preferable to an Olympic experience. But now he has neither.

Yet, as Espineli packed his bags Thursday morning, he repeated that the course of events left him with no regrets.

"Like I've said, I'd like to do both, but there's almost nothing I wouldn't pass up to get my first big league shot," said Espineli, who was 1-0 with a 5.40 ERA in nine outings. "Hopefully I've shown through my good outings that I have the ability to get big league hitters out."

To clear room for Palmer on the 40-man roster, the Giants transferred right-hander Merkin Valdez, who's still nursing a strained right elbow, from the 15-day disabled list to the 60-day DL.