He's been out for just over 3 weeks now. If he's out for another 4 weeks that would take us to 6 Oct. That takes us to the October Internationals week. The next game after that international break is Villa at home (18 Oct). That would mean (Prem league wise) he'd miss another 4 games (WBA, Palace, RS, and Man Utd). Right now I'd take that even though he's going to miss The Derby no doubts.