Arsenal midfielder Jack Wilshere has undergone a successful operation on his right ankle, but could be out for up to five months, the Premier League club announced.
The 19-year-old suffered a stress fracture to his right ankle in a pre-season friendly against the New York Red Bulls.
"The initial indications are that the surgery has been successful and Jack will now undergo a prolonged period of rehabilitation. It is envisaged that Jack's rehabilitation will take a period of four to five months," Arsenal's statement said.
Wilshere added: "I've had my operation this morning and all went well. My ankle is little bit sore, but Im already looking forward to working hard to get fit and playing again.
"I would also just like to say thanks for the many messages of support I have received from you: the fantastic Arsenal supporters. See you all soon at the Emirates."
The news will add further pressure on Arsenal manager Arsene Wenger as his side have made a dreadful start to the Premier League campaign after struggling to overcome the departures of Samir Nasri and captain Cesc Fabregas.