Alexis Sanchez ran down his Arsenal contract and engineered a move to Manchester United but he still has the sympathy of his former manager.
Wenger claims it was “very difficult” for the Chilean because his commitment was constantly in question from the media.
Sanchez himself has explained why he moved to United, saying they are the biggest club in England.
“Sanchez, for him it was very difficult because as soon as he had a game that was average he was questioned about his commitment and that is not his case,” Wenger told BT Sport.
“When he is on the football pitch he wants to win. But it was a bit unfair to him I think.
Asked if Sanchez was unsettling the rest of the Arsenal squad, he said: “I don’t know, our results in the future will show that.
“What was a bit unfair to Sanchez: he was questioned every time. Is he committed or not committed?
“There was always a debate and then, of course, it starts to unsettle a little bit but I never questioned his commitment but it was a difficult situation.”