Amari Cooper has missed two full games and most of two others this past month. Denver safety Darian Stewart set this course with a vicious, though not altogether dirty hit that concussed Cooper on Nov. 26 and sprained his ankle. The ankle was an afterthought then, but it remains the cause of his prolonged absence. He missed the following game against the New York Giants, but pushed to play a crucial AFC West showdown at Kansas City. Cooper’s ankle got rolled while blocking for the run against the Chiefs, and he ended up back on the shelf for a Sunday night loss to Dallas. The Raiders hope Cooper can return for next week’s road game at Philadelphia. He worked on the side with trainers during Thursday’s practice, and will try and play the Eagles on Christmas. “We hope to get him back to practice and have a good week of practice,” head coach Jack Del Rio said, “and be ready to go Monday night.” That would immensely benefit the Raiders offense. This hasn’t been a season to remember for the two-time Pro Bowler, but the Raiders have missed him in the pattern. His athleticism, route running and big-play ability demands significant attention. “You’re covered differently when Coop isn’t demanding roll to him or attention that he normally gets,” Del Rio said. “Not having Coop, you feel the difference because he’s such a dynamic, explosive playmaker for us.” Cooper’s career started with consecutive 1,000-yard seasons. He has struggled some this year, with just 42 catches for 499 yards and five touchdowns. Roughly 40 percent of that yardage total game in one game. The Chiefs let him roam, over 11 catches for 210 yards and two touchdowns, where he was his typical, explosive self. Something’s been missing outside that. He has 10 drops on the year, exposing a major issue as a rookie that got cleaned up his second year.