Defensive end Anthony Spencer needs microfracture surgery on his knee and is likely done for the season, owner Jerry Jones said Tuesday on his radio show.
Jones told KRLD 105.3 FM "The Fan" that he learned the news Monday night.
Spencer has been trying to recover from arthroscopic knee surgery July 25. But loose cartilage remained a problem, he said last week, and bone was still making contact with bone.
Spencer played 34 snaps against Kansas City in Week 2 after a limited practice week. He practiced only one day in preparation for the Rams game and then was inactive on game day.
Spencer said last week that microfracture would not be necessary.