Portugal centre back Danilo Pereira (31) suffered three broken ribs in training, the team said on Sunday, putting his participation in the team's World Cup campaign in doubt.
Portuguese media reported that he is ruled out of the group stage and should Portugal make it to the knockout rounds, it is also doubtful that he will be fit to play.
Pereira suffered the injury in Saturday's training session.
Portugal are top of Group H after beating Ghana 3-2 in their opening game on Thursday. They face Uruguay in their second group match at the Lusail Stadium on Monday.