Xhaka joined Arsenal from Borussia Monchengladbach in the summer with a reputation of being a little too fierce at times, though Wenger says that those previous reds are now in the past and nothing can be done to change that.
Asked if he felt the need to speak to Xhaka after the latest incident, the Frenchman told reporters: "Yes. But it is one and we are not responsible for the red cards he got somewhere else.
"He made a foul that could have got him a yellow or red card and it was not meant to hurt anybody. But I feel he is intelligent enough to analyse that as well."
Wenger confirmed earlier this week that he does not intend to appeal the decision to dismiss the £30m summer signing.