San Francisco Giants lefthander Noah Lowry, attempting to return from two arm operations that cost him the 2008 season, had a setback when he felt tightness in his left elbow Wednesday.

He won't throw again until the weekend.

"His elbow has been a little cranky. With everything that has happened to this point, it's very questionable whether he'll be ready" for the start of the regular season, manager Bruce Bochy said.

Lowry underwent surgery on his left forearm for a condition known as exertional compartment syndrome on March 7, 2008. He underwent arthroscopic surgery on his left elbow on Sept. 30.

Lowry experienced tightness in his left scapula early in spring training and has not thrown a full bullpen session.