Wenger is satisfied that the Spaniard has put his injury behind him - in more ways than one.
"He has had two more weeks of practice behind him and in the last two or three days he has looked sharp," said the manager.
"It is more a restriction he has when he comes on because it [the hamstring injury] is in his head. So we have to move the hamstring out of his head and that comes with practising every day.
"Physically I think he is ready. At the moment in winter one of the disadvantages, when it is so cold, for the guy who comes on with 25 minutes to go is that it is not easy to get into the flow of the game.
"He had as well a little bit the mental problem, but now it looks to have gone.
"It is hard to overcome if you have a recurrence of injuries because it plays a part until you get rid of it completely by reassurance. The fact he has played 30 minutes [against Man United] has helped him, but during that 30 minutes he was not himself completely."