Mustafi only signed for the Gunners last year in a £35m move from Valencia but hasn't enjoyed the best of times since his arrival.
Wenger held his cards very closely to his chest when asked about selling Mustafi but certainly didn't rule it out.
He said: "I don't expect... it's difficult for me to speak about individual cases. We are now in the final seven days of the market. It's always difficult to predict, you have to make sharp decisions."