The England international was introduced 65 minutes into the Gunners’ clash with Norwich on Saturday, but was substituted just nine minutes later after suffering from a knock to his hip.
A solitary goal from Grant Holt proved enough to gift the Canaries all three points against an Arsenal side that struggled to create clear-cut chances at Carrow Road.
"It was a kick on his hip. It is not long-term but he will be out for Wednesday," he told ESPN.
"I don’t see anyone new being [back] for Wednesday night. The closest will be Gibbs but he will not be ready. Walcott will not be ready [either]."
|4/6||Arsenal's clash with Schalke is 4/6 with PaddyPower to feature over 2.5 goals
Wenger admitted he had considered introducing Jack Wilshere against Norwich, but he felt that neither the midfielder nor the side as a whole would have benefited.
"We have to be conscious he has not played for 14 months," the Frenchman added. "I would have brought him on if the game had allowed it today, but it was too intense.
"He will play on Monday with the reserves and then we will see where we go from there. He needs games."
Wenger bemoaned a "sharpness" that his side failed to muster at Carrow Road and hopes that the result will spur them on to give a better performance against the Bundesliga side in midweek.
"I hope it will have a positive impact," Wenger said. "It was a shock to the system today. But you have to give credit to Norwich today.
"They played well and were completely committed and they deserved the win. Maybe we underrated the difficulty we would face.
"I felt we lacked a bit of sharpness. We tried to get into the game after 20 minutes. But we missed what makes the success at the top level - that is complete focus. And they were sharper than us.
"It is not an excuse. We have to deal with that. You could say we have better players but there is only one way to show that – on the football pitch.
"We do not blame anybody, we made many mistakes today. We have to put that performance behind us and realise that is not good enough - and come out on Wednesday with a different performance.
"The attitude of the team has been excellent but that was not at the level of what we have produced until now. It was the first time of the season we were way below par. And we were well below today."