Xhaka was stripped of the club captaincy earlier this week after he tossed the armband and twice instructed Arsenal fans to "f--- off" when they booed him during his substitution against Crystal Palace on Oct. 27.
The midfielder has now missed all four matchday squads since the incident after informing his boss he's not ready for this weekend's action.
"I don't know if he's going to play again. I don't know if he is available in his mind to continue helping us and continuing defending the Arsenal shirt," Emery said, according to BBC Sport.
He added: "Then, if I decide he is in the group with us, if he is ready and 100% in his mind with the decision to help us and to play with his quality helping us. We need that quality and that player.
"We're now a little weaker without him in that position because we have one less player."
Emery also revealed that he has spoken to the club about the possibility of replacing Xhaka in January, but he was reluctant to delve any deeper into Arsenal's plans during the next transfer window.
"I'm not thinking about that because we're in November and we're going to play a lot of matches in November and December," he said. "We cannot change him in that two months. The club is speaking with him and we're going to decide how he is and how I'm thinking we use him."