The midfielder has been on the sidelines since incurring an ankle problem in an Emirates Cup game with New York Red Bulls in July 2011.
His return to action was further delayed when he suffered a setback in January and Gunners boss Wenger remains cautious about trying to predict when he may return to action.
"It is impossible to set a concrete deadline at the moment, but it is all okay," the Frenchman told Arsenal Player.
"He is as quick as we expected him to be. His ankle is good and his knee is good. There is no setback. It is difficult to say 'it will be this week in September or October' when he is back in training.
"He has been out for a year and I don't want to put any pressure on him."
Meanwhile, midfielder Tomas Rosicky and defender Bacary Sagna are likely to miss the start of the new campaign, although the latter should be back by the end of August.
But Emmanuel Frimpong, who injured his knee while on loan at Wolves earlier this year, will not feature until late September at the earliest.