Wenger was asked if he was surprised Manchester United chose to release the Armenian to them.
He said, "He didn't play there so I was not too surprised. He was not playing at Manchester United and they got one more player who plays in a similar position with Sanchez.
"I am not responsible for Manchester's decisions. I am responsible for Arsenal's decisions - that is enough for me. They had their reasons. They have a world-class player in Sanchez and that obstructed him."