The England international had been excellent for the Gunners during the first part of the season and bagged 10 goals in 18 appearances by the turn of the year, but since agreeing a new deal he has scored just once, against Liverpool over two months ago.
However, Wenger does not believe that his drop in form and new contract are related, adding that the former Southampton man looks as hungry as ever, backing him to find his form again in the near future.
"I don't believe that," Wenger said to reporters. "If he didn't play well and had not signed a contract, then people would say the opposite.
"I don't think that is linked, especially with the fact that he has signed a contract or not. Because you can say as well he is more secure, he can express himself.
"I don't see any difference in attitude in training. He is a guy who loves football, who stays after training, works on his finishing.
"He was just a bit less decisive. He needs that fraction of a second to make the difference. He needs his pace.
"In recent games he dropped a little bit. I think it was the fact that he got the muscular injury, so it was down to fatigue.
"At Bayern, he did not have the greatest game but he still brought the goal and he looks dangerous. Until recently he made the difference time after time. He will come back."