Dallas Cowboys defensive end Anthony Spencer will undergo a microfracture procedure on his left knee that will sideline him for the remainder of the 2013 season.
Cowboys owner Jerry Jones first suggested the possibility that Spencer would need surgery during a radio spot on 105.3 FM "The Fan" in Dallas on Tuesday morning. Spencer's agent, Jordan Woy, confirmed that his client will go under the knife via Twitter later in the day.
"It's a real setback," Jones told the station according to the team's website. "(He) could be out for the season."
Woy tweeted that Spencer is expected to be at 100 percent by January or February.
Spencer had a previous surgery on the same knee at the end of the July and sat out Dallas' season opener against the Giants while recovering. The 29-year-old returned to action for the Cowboys' Week 2 loss at Kansas City, but was inactive again during this past Sunday's 31-7 win over St. Louis.
The injury is a significant blow for both Spencer and the Cowboys. The 2007 first-round pick is coming off an outstanding 2012 season in which he set career highs of 11 sacks and 95 tackles, plus Spencer will be an unrestricted free agent in the offseason after being designated as Dallas' franchise player for 2013.