Sanchez only arrived back in London on Thursday after missing out on World Cup qualification with Chile and boss Arsene Wenger says the club will check on his physical and mental well being before deciding whether to include him in the match-day squad.
There was better news on Ozil and Welbeck though, both having overcome knee and groin injuries respectively.
Shkodran Mustafi suffered a hamstring injury over the international break and is set to be out for four to six weeks, leaving Wenger short of options at the back, although the Frenchman remains philosophical over the setback.
"It's always difficult to predict the situation because the player I least expected to lose during the break was Mustafi," said Wenger. "First of all, I was not sure he would play. Secondly, Germany had already qualified so I didn't expect him to be out injured as the games would be less intense. He didn't play in the first game, and we lost him in the second game against Azerbaijan at home. We have to cope with that now."
The Gunners also have concerns over Laurent Koscielny (Achilles) and Sead Kolasinac (hip) and both will be given late fitness tests. Calum Chambers (hip), Francis Coquelin (hamstring) and Santi Cazorla (ankle) are all out.
Provisional squad: Cech, Ospina, Macey, Koscielny, Mertesacker, Holding, Monreal, Kolasinac, Bellerin, Debuchy, Elneny, Xhaka, Maitland-Niles, Ramsey, Wilshire, Ozil, Walcott, Sanchez, Welbeck, Lacazette, Giroud, Akpom.