Arsenal midfielder Jack Wilshere requires surgery on a hairline fracture in his left leg and is set to be out for around three months.
Wilshere, 23, has struggled with a series of injuries and missed five months of last season with ankle ligament damage.
The England international has also not played so far in the 2015-16 campaign after suffering a hairline fracture in training ahead of Arsenal's Community Shield win over Chelsea.
Following further medical examinations, the decision has now been taken that an operation is needed to properly correct the problem and will take place in the next few days, while it will require a metal plate to be placed in Wilshere's leg.
.@JackWilshere is to undergo surgery to his left fibula in the coming days. Full story: http://t.co/khWvsDFSoe pic.twitter.com/pSyAyoO1Hu
- Arsenal FC (@Arsenal) September 15, 2015
An official Arsenal statement read: "Due to a slow healing response from a fracture suffered in August, the club can confirm that Jack Wilshere is to undergo an operation to his left fibula.
"The decision to intervene has been taken quickly after regular reviews by specialists, who feel that Jack's scans show that the healing process is not progressing as well as expected.
"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. Everyone at the club wishes Jack well with his rehabilitation."
The news will come as a blow to both the player, who has battled through a string of fitness issues in recent seasons, and the club, with Danny Welbeck also set for an extended spell on the sidelines until at least Christmas following knee surgery.
Arsenal travel to Croatia for Wednesday's Champions League opener against Dinamo Zagreb on the back of a 2-0 victory over Stoke, which sustained their recovery in the Premier League.
Theo Walcott, who once netted a hat trick playing for England at the Maksimir Stadium, is pressing for another start after scoring the opening goal against the Potters on Saturday.
Per Mertesacker is not expected to take part, having just recovered from a virus and also being involved in a minor road traffic accident on Monday.
Information from the Press Association was used in this report.