Spencer underwent minor knee surgery and missed most of training camp and the season-opening win over the New York Giants before finally getting onto the field in last week's loss to the Kansas City Chiefs. The veteran defensive end saw limited action against the Chiefs and did not practice on Wednesday or Friday.
The seventh-year player enjoyed a career-season in 2012, totaling 95 tackles, 11.0 sacks and two forced fumbles. With the Cowboys making the transition back to the 4-3 under defensive coordinator Monte Kiffin, Spencer was expected to form a formidable pass-rushing duo with DeMarcus Ware.
Defensive end George Selvie will once again get the start on Sunday in Spencer's place, with the hope that Spencer will be able to split snaps as he continues to work through the sore knee.