OXNARD, Calif. - Dallas Cowboys starting defensive end Anthony Spencer hopes to be back in two to three weeks after undergoing successful surgery on his left knee Thursday in Dallas.

"It went well," Spencer's Dallas-based agent, Jordan Woy said.

Spencer suffered a hyperextended knee during offseason workouts and re-injured the knee during his conditioning test at training camp last Sunday. An MRI revealed a bone bruise and minor surgery became an option.

Spencer, who was second on the team with 11 sacks in 2012, said he hopes to play in one preseason game and expects to be ready for the regular season opener against the New York Giants on Sept. 8 at AT&T Stadium.

Ben Bass has been taking first-team snaps at end in Spencer's place.