Reece James is set to be out of action for eight weeks, putting his place in Gareth Southgate's England World Cup squad in doubt.
The full-back suffered the injury in Chelsea's UEFA Champions League win over AC Milan at San Siro in midweek after 62 minutes of action.
According to the club's official website the defender is facing up to eight weeks on the sidelines.
"Following the knee injury sustained in our away match against AC Milan, Reece has received treatment from the Chelsea medical department and visited a specialist this weekend.
"After consultation between all parties, Reece will now undergo a rehabilitation programme and is expected to be out for eight weeks."
It is believed that ligament damaged was found in the scans, but fortunately the injury will not require surgery.
With the World Cup just around the corner - England's first game is on 21st November - and Southgate set to name his provisional squad for the tournament in the next week however, James may not be selected.
James isn't the only England right-back option who has suffered an injury setback in recent weeks, with Trent Alexander-Arnold hobbling off injured last Sunday in Liverpool's 3-2 defeat to Arsenal at the Emirates Stadium. TAA's injury isn't as severe as James' however, as he is expected to miss just two weeks of action with an ankle injury.