Arsenal manager Arsene Wenger has confirmed that Kieran Gibbs will be absent for two to three weeks with a hamstring injury.
The defender suffered the problem during the Gunners' opening Premier League 2-1 victory over Crystal Palace on Saturday evening at the Emirates.
The injury blow means that Gibbs will miss the first leg of Arsenal's Champions League playoff against Besiktas in Turkey tonight, as well as the return fixture at the Emirates.
Meanwhile, Laurent Koscielny has recovered from an Achilles knock to feature for the North London outfit.