The England international has not appeared for Arsenal this year due to a calf injury.
But he has since returned to training and is available to face his former club on Saturday.
Chelsea and Arsenal squads enjoy team meals out, but where is Mesut Ozil?
Wed, January 25, 2017
Chelsea and Arsenal both enjoyed team meals out ahead of their FA Cup games this weekend, but Mesut Ozil was mysteriously absent from the Gunners' dinner
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Chelsea and Arsenal both enjoyed team meals out on Tuesday evening
Arsenal forward Theo Walcott
Wenger said: “Walcott back in the squad and of course we lose Xhaka who is suspended.
“Good news is that Mertesacker & Debuchy back in full training tomorrow.
“I have not decided yet completely who will play and not play.”