Arsenal's injury woes continued on Monday after Thomas Vermaelen was ruled out for up to three months with an ankle injury.
The centre-back injured his left Achilles in the Gunners' UEFA Champions League qualifier against Udinese and did not feature in the club's 8-2 humiliation against Manchester United.
Vermaelen is believed to have undergone surgery on Monday after consulting a specialist in Stockholm and will be out of action until December.
The news further compounds manager Arsene Wenger's injury concerns ahead of their home game against Swansea on Saturday. With Laurent Koscielny a doubt after picking up an injury during the side's home loss to Liverpool and Jack Wilshire out for up to three months with an ankle problem, Wenger will look to new signings Mikel Arteta, Yossi Benayoun, Andre Santos, Park Chu-Young and Per Mertesacker to assume greater responsibility.
Wilshire is by far the greatest loss for the Gunners boss, after the midfielder suffered a recurrence of the ankle injury that plagued his pre-season.
England manager Fabio Capello has questioned Arsenal's treatment of the midfielder, after the 19-year-old aggravated the problem during England's 2-2 draw with Switzerland in June.
Arsenal allowed Wilshire to go on holiday during the summer break only for the injury to flare up again in a club friendly in June. Asked if he believed Wenger had made a mistake by not treating the injury sooner, Capello said:
"It's not my job to say what happened but he suffered [the injury] against Switzerland and then went on holiday for a month."
Meanwhile, Wenger will serve out his two-match Champions League touchline ban after UEFA rejected the club's appeal.
The Frenchman was handed the punishment after officials spotted him conveying messages to his technical staff while already serving a ban carried over from last season.
"The UEFA Appeals Body has rejected the appeal lodged by Arsenal and Arsene Wenger against the two-match suspension handed to the manager in the wake of the English club's UEFA Champions League play-off first leg against Udinese Calcio on 16 August," a statement from UEFA said.
"Wenger will now be suspended from carrying out his duties at Arsenal's next two UEFA competition matches...in accordance with the decision taken by the UEFA Control and Disciplinary body on 22 August.
"The manager was awarded this suspension for not abiding by an earlier decision of the Control and Disciplinary Body during the Udinese home game - in which Wenger was serving a one-match ban imposed following Arsenal's final UEFA Champions League game of last season.
"The Control and Disciplinary Body also fined Arsenal €10,000 for improper conduct by their officials during last month's match against the Italian team in north London."
Wenger will miss the first two matches of the group stage, away at Borussia Dortmund and at home to Olympiakos.