Arsenal is already without Calum Chambers for at least another week, while vice-captain Laurent Koscielny will undergo a final fitness test on Friday to determine his availability. Left-back Sead Kolasinac, however, should shake off a hip concern.
"I don't think he will be available before the next international break (in November)," Wenger revealed to Reuters of the thigh injury Mustafi suffered in Germany's 5-1 trouncing of Azerbaijan on Sunday.
If Koscielny overcomes a strained Achilles, he would likely assume a place in Wenger's back-three with in-form Nacho Monreal and Rob Holding. That would leave veteran Per Mertesacker warming the bench, and Kolasinac acting as an auxiliary option should more defenders fall to injury.
Elsewhere in the Gunners' lineup, Alexis Sanchez will be assessed closer to game time after representing Chile in a 3-0 loss to Brazil on Tuesday. Wenger noted that his forward received some rough treatment from the home side in Sao Paulo.