Dallas Cowboys defensive end Anthony Spencer is done for the season, according to his agent, Jordan Woy. Spencer will undergo microfracture surgery on his left knee that will keep him sidelined until January or February.
Spencer underwent surgery on the same knee in July and recovered quickly enough that he was able to play in the Cowboys' Week 2 game against Kansas City. However, Spencer was held out of practice leading up to Dallas' Week 3 game against the Rams and ended up not playing against St. Louis.
Cowboys owner Jerry Jones did a radio interview with KRLD-FM in Dallas on Tuesday morning and mentioned that Spencer's season might be over.
"It's a real setback," Jones said. "He was so diligent in his rehab. The individual that I have the most empathy for is Spencer because of the type of person he is."
Before 2013, Spencer had started in 61 of the Cowboys' past 64 regular-season games.
With Spencer out, the Cowboys will need fourth-year player George Selvie to step up. With Spencer hobbling through the season's first three weeks, Selvie has already seen substantial action in 2013. The 26-year-old has started all three games this season, the first three starts of his career, and has tallied two sacks.
Spencer's injury is the second one this week that shows the risk of being franchise-tagged. Spencer was given the one-year tag by the Cowboys in March and will now have to rehab the knee and prove he can play before a team will sign him in free agency next year.
Bears defensive tackle Henry Melton is another franchise-tagged player that suffered a season-ending injury recently. Melton will miss the rest of the season after tearing his ACL in Chicago's Week 3 win over Pittsburgh.