Anthony Spencer having surgery

IRVING, Texas -- Dallas Cowboys defensive end Anthony Spencer is undergoing microfracture surgery on his left knee Tuesday, according to his agent, Jordan Woy.

Woy said Spencer should be 100 percent by January or February.

Spencer was placed on injured reserve last week and looked at several surgical options before settling on the microfracture operation that will also use stem cells to promote cartilage growth.

In the surgery, tiny holes are drilled into the bone, and blood and bone marrow seal the fractures, creating a super-clot that turns into cartilage over time.

Spencer is in the final year of his deal with the Cowboys and is set to be a free agent in March. Owner and general manager Jerry Jones said he would like Spencer to return to the Cowboys, but the team faces salary-cap issues in 2014.

George Selvie has replaced Spencer, who played in only the 17-16 loss to the Kansas City Chiefs, and has recorded three sacks. Spencer had surgery on July 25 and missed most of training camp and all five preseason games.