Arsenal will be without some key players for their clash with Watford this weekend.
The Gunners return to domestic matters after the latest international break, hoping they can continue their impressive recent form.
However, they will have to do that without Shkodran Mustafi after the German international suffered a muscle tear while playing for his country earlier this week.
Speaking to ESPN about the centre-back, Wenger said, "I don't think he will be available before the next international break."
That comes in November, meaning that Arsenal look set to be without the defender for at least their next seven matches in all competitions.
With Laurent Koscielny also fighting to be fit, that leaves Arsenal short at the back just when they will be hoping to push on and get back into the top four.
The good news for Arsenal is that most of their matches in the next few weeks are winnable if they play to their full potential, even with a weakened defence, although the game against Manchester City next month is another matter.
"Koscielny has a definite final test tomorrow," the Arsenal boss added. "At the moment he is not available."
Arsenal have had plenty of injury problems with their defenders in recent seasons, but their switch to three at the back has at least limited the impact of some of those absences, with the likes of Nacho Monreal and Sead Kolasinac impressing in the new-look formation.
The Arsenal defender's injury is yet another example of why many club managers hold their breath for the duration of each and every international break, hoping their players return as they left.