Danny Welbeck has undergone surgery on his left knee and will be out for "a period of months," Arsenal have announced.
Welbeck, 24, sustained a knee injury in April, and had been working towards a comeback in training for the Gunners.
However, the Premier League club have announced that the former Manchester United forward has instead undergone surgery and will now be out of action for an extended period of time.
#Arsenal forward Danny Welbeck has undergone surgery on his left knee. Full story here: http://t.co/x90WdtcGND pic.twitter.com/x0THO1LhcZ
- Arsenal FC (@Arsenal) September 3, 2015
A statement on the club's official website read: "Danny Welbeck has undergone surgery on his left knee after being unable to sufficiently step up his rehabilitation work.
"The striker has been working throughout the summer to recover from the injury sustained at the end of April.
"It had been hoped he would avoid surgery but after increasing his training workload, the injury to his cartilage did not respond as well as hoped and the decision was taken last week for him to undergo surgery by a leading specialist in the field.
"Danny is now expected to be out for a period of months and everyone at Arsenal wishes him well."
Arsenal were the only side in the top five European leagues not to sign an outfield player this summer -- only bringing in goalkeeper Petr Cech from Chelsea -- with Arsene Wenger claiming that Manchester United's £36 million signing of Anthony Martial shows that big clubs have to pay over the odds to improve their squads.
Gunners midfielder Alex Oxlade-Chamberlain said in a news conference with England this week that he was happy with the club's summer transfer business, adding: "We've got great depth in numbers and when you look at the likes of Danny Welbeck and Tomas Rosicky to come back from injury, we've got really good options."