Arsenal manager Arsene Wenger has revealed that Laurent Koscielny will be sidelined for six months as a result of the Achilles injury he sustained during the Gunners' Europa League defeat to Atletico Madrid last Thursday.

Koscielny was stretchered off after just 12 minutes of the match at the Wanda Metropolitano, with Wenger confirming after the game that the 32-year-old was likely to miss the World Cup.

However, the damage is worse than first feared and the France international will now miss at least six months of action, with his return expected to come in December.

"Koscielny is of course devastated because he needed surgery," Wenger told reporters at a press conference.

"That means he will be out for six months. You will not see him at the beginning of December at best."

Koscielny had been planning to retire from international football after this summer's World Cup in Russia.