Arsene Wenger has revealed Theo Walcott may not take part in Arsenal's Champions League clash against Schalke on Tuesday evening due to an illness.
Walcott, who netted a hat-trick for the Gunners in last week's comeback victory over Reading in the Capital One Cup, did not start against Manchester United on Saturday.
He will be given until the day of the Champions League game to prove his fitness, but Wenger's tone suggested he is preparing to be without Walcott's services.
"[Walcott] has been sick overnight [and] didn't practice [Monday] so we have to see how he is on Tuesday morning," Wenger said.
In a boost for Arsenal, Jack Wilshere appears set to start after impressing since his returning from a long-term ankle injury.
"I think I will play him [Wilshere]. Then we have a block of three games and maybe the fact that he gets a period of recovering will be just right for him. He gets better in every game."
Aaron Ramsey will miss the Schalke match with a groin strain, with Johan Djourou tipped to replace him in the squad.