Irving, TX (Sports Network) - Dallas Cowboys defensive end Anthony Spencer underwent successful microfracture surgery on his left knee on Wednesday.
Spencer didn't play during the preseason while recovering from a similar operation in mid-July and sat out the club's season-opener against the New York Giants before returning for the Week 2 contest against Kansas City.
The 29-year-old Purdue product notched a pair of tackles in the loss to the Chiefs, but was inactive the following week against St. Louis before being placed on season-ending injured reserve on Sept. 25.
A 2007 first-round pick, Spencer was coming off an outstanding 2012 season in which he set career highs of 11 sacks and 95 tackles. He is set to become an unrestricted free agent in the offseason after being designated as Dallas' franchise player for the past two seasons.