Coach Wade Phillips said LB Anthony Spencer will miss 2-4 weeks after undergoing arthroscopic surgery on his right knee Wednesday

The Cowboys first thought Spencer's injury was just a bone bruise and called him day-to-day, but doctors decided it need to be cleaned up with surgery this week. "It kept getting irritated," Phillips said. "It'd go down and then it'd go back. There was just a particle in there that kept catching."
Source: Dallas Morning News