Arsène Wenger has confirmed the France defender Mathieu Debuchy will be out of action for three months following ankle surgery.

Debuchy – signed from Newcastle for £12m in the summer – sustained ankle ligament damage in Arsenal’s 2-2 draw with Manchester City last week and is not likely to play again until Christmas, with Calum Chambers expected to deputise in his absence.

“He had surgery on Friday and will be out for three months,” said the Arsenal manager. “A reasonable delay is three months. All went well. It can be a week or two earlier or a week or two later but it will be around three months.

“It is a blow. How big it will be we will only know afterwards because it will be down to how well we replace him. We bought Chambers for that.”

Wenger also confirmed Nacho Monreal’s back problem means the left-back is not expected to return until after next month’s international break. Yaya Sanogo, Theo Walcott and Serge Gnabry are also likely to be sidelined until next month, with a host of young players, including Héctor Bellerín, Francis Coquelin and Isaac Hayden, all in the frame to feature against Southampton in Tuesday’s Capital One Cup tie.“On Tuesday night you might see Héctor Bellerín, Francis Coquelin and Isaac Hayden. In the squad we have Chuba Akpom and Semi Ajayi as well. These are the players that are the closest,” Wenger said.