BOSTON -- The Boston Red Sox learned yesterday that designated hitter Andre Dawson will undergo arthroscopic surgery on his left knee today. He could be out four weeks.

Dawson, 39, hitting .246 with 10 homers and 27 RBIs in 36 games, suffered a "locked" knee while running to first Tuesday night against Cleveland. He had a magnetic resonance imaging test yesterday morning that showed an object -- either a bone chip or a fragment of cartilage -- lodged in the joint of the knee. He was placed on the 15-day disabled list yesterday.

This will be his ninth knee surgery, and the fourth on his left knee -- which is considered the more troublesome. It's his second arthroscopic surgery since joining the Red Sox before the 1993 season. He had arthroscopic surgery last year on his right knee and missed 18 games in May. Team physician Arthur Pappas will perform the surgery.