Wenger has struggled to get the best out of him in recent seasons due to injury and some Gunners fans have questioned whether the England midfielder will ever get through a campaign unscathed.
"This is a big season for Jack but he is in his best pre-season shape for three years," he said.
"At the top level you need consistent presence. It does not work anymore when you rest for three weeks and then you are fit again - in and out is finished today.
"He is rid of his ankle problems and if he can maintain that I think he will have a great season. But he needs games and I agree that this is a very important season for him."
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