Arsenal midfielder Jack Wilshere will be sidelined for "approximately three months" as his injury is worse than initially thought and requires surgery.
The 23-year-old fractured his left fibula in August, and the Gunners have revealed that "the healing process is not progressing as well as expected".
The club statement added: "Jack will have surgery in London in the forthcoming days. This will involve inserting a small plate in his left fibula. Jack is likely to be out for approximately three months."
Wilshere will have to watch from the sidelines as Arsene Wenger's side kick off their Champions League campaign away to Dinamo Zagreb on Wednesday before facing Chelsea in the Premier League at Stamford Bridge on Saturday.