Arsenal manager Arsene Wenger has admitted that the extent of midfielder Mesut Ozil's injury is not yet known.
The German international suffered a hamstring problem during the Gunners' 1-1 draw with Bayern Munich, which booted them out of the Champions League on Tuesday.
Wenger has confirmed that Ozil will play no part in Sunday's North London derby against Tottenham Hotspur, but he is unsure for how long the former Real Madrid star will be on the sidelines.
"He is out," Wenger told the club's official website. "I don't know for how long but it is a hamstring injury. There are scans going on."
Aaron Ramsey has also been ruled out of the derby, while Kieran Gibbs and Nacho Monreal have a "good chance" of being fit.
