Manchester City suffered a blow brought on by the World Cup as Ruben Dias was ruled out for up to a month.
Sportsmail understands Dias encountered a problem with his thigh during Portugal's last-16 victory over Switzerland but continued to play during the tournament.
The central defender remained on the pitch for the full 90 minutes as Portugal were dumped out by Morocco four days later and has not trained with City since his return from Qatar.
An initial assessment suggested that Dias, one of the club's five captains, will miss City's next five games after their 3-2 win over Liverpool in the Carabao Cup.