"The A's placed first baseman Jason Giambi on the 15-day disabled list Monday with a strained right quadriceps, adding to what's been a frustrating season for the veteran slugger.

Giambi has battled sore legs all season, but he's played the majority of innings at first base even as his average has plummeted to .193, lowest in the major leagues among everyday players.

He wasn't available to reporters Monday. But general manager Billy Beane and manager Bob Geren indicated the quad injury has accumulated over time.

The A's recalled Daric Barton from Triple-A Sacramento for his second stint with Oakland this season. Barton started at first base Monday against Minnesota.

"He's had some nicks and pains for a while now," Beane said of Giambi. "All things considered, this is probably the best approach. It gives us a chance to play Daric. He's swinging the bat very, very well."

Giambi is eligible to come off the DL on Aug. 4, but there's no indication if he'll be ready by then.

Barton turns 24 in August. He was pounding the ball for Sacramento since being optioned June 28 and mashed a two-run homer in his second at-bat Monday.

Beane sounded as if the A's might stick with Barton at first if he hits, even when Giambi returns."