Arsene Wenger has insisted that Jack Wilshere is progressing well in his recovery from injury but he will not put the Arsenal midfielder under any pressure to return by a specific date.
Wilshere missed the whole of last season because of an ankle problem sustained on international duty, while a long-standing issue with the patella tendon in his left knee then flared up during his rehabilitation.
He was sent for knee surgery in May and Wenger is happy with the condition of Wilshere's knee and ankle, although he will not rush the 20-year-old back into action.
"It is impossible to set a concrete deadline at the moment," Wenger told the club's official website.
"But it is all OK. He is as quick as we expected him to be. His ankle is good and his knee is good. There is no setback.
"It 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."
Wilshere is one of the Arsenal players not travelling out to Asia for the club's pre-season tour, as Wenger gears up for the start of the new Premier League campaign.
Tomas Rosicky (plantaris tendon), Bacary Sagna (broken fibula) and Emmanuel Frimpong (knee) look set to miss the first few weeks of the season but the likes of Abou Diaby, Mikel Arteta and Lukasz Fabianski are fit after missing the end of last term.
"Some players like Walcott and Oxlade-Chamberlain, they travel. Song, Diaby, Vermaelen, Santos, Gibbs, Szczesny, they will all travel," said Wenger.
"So will Gervinho - we have a very strong team out there. Rosicky is injured. Apart from that I think everybody travels."
Expanding on the news about Rosicky, Wenger added: "It will be six to eight weeks until he is back in training. It was his [plantaris tendon], it was done at the Euros.
"Emmanuel (Frimpong) is doing very well. It will be the end of September or perhaps into October for him."
Speaking about Sagna, Wenger added: "He is doing very well. There are no problems there. But it will be the end of August for him."