Arsenal defender Sead Kolasinac will be out for between eight and 10 weeks with an injury to his left knee.
The Bosnian picked up the blow during the Gunners victory over Chelsea in the International Champions Cup on Wednesday evening.
Kolasinac clashed with Blues defender Victor Moses and was forced off the field after 70 minutes.
Manager Unai Emery confirmed the full-back was to have a scan following the injury, and he club have now since confirmed he will be ruled out for up to eight Premier League games with the injury.
The Bosnia and Herzegovina international is also likely to be absent for two Europa League group matches and the third round of the Carabao Cup.
Kolasinac joined Arsenal last summer from FC Schalke, and made 27 appearances in all competitions for the Gunners last season, scoring twice and producing four assists.