Cowboys receiver Terry Glenn had arthroscopic surgery on his right knee for the second time in six weeks Thursday. Glenn reinjured his knee last week when he tried to return to practice for the first time since the initial surgery Aug. 1 to remove a cyst. That was a week into training camp. "This gives Terry a chance to play this season," Cowboys spokesman Rich Dalrymple said. "He will do everything he can to get on the field this year." Still, the team said there is no timetable for Glenn's return.