Arsene Wenger believes the Gunners' Champions League encounter with AZ Alkmaar in midweek will be too soon for Theo Walcott to feature in, as the winger injured his knee following a tackle from Birmingham's Liam Ridgewell, during Arsenal's 3-1 victory. "He has a bruised knee, it is swollen and difficult to assess at the moment. Is it a medial knee ligament that is twisted or just a kick? The fact that he says he felt a little unstable when he was running is not good news. "We will assess the situation tomorrow morning. He will be scanned and if it is just a kick he has a good chance to play on Tuesday night. If it is more, he will not play on Tuesday. "I believe personally he will not be available on Tuesday at least. It is not a cruciate for example but it could be more than a week if it is a twisted ligament."