Real Madrid forward Cristiano Ronaldo will be sidelined for three to four weeks after he aggravated an ankle injury in Portugal's 3-0 win over Hungary.
He had sprained his right ankle in a match against Olympique Marseille last month and limped off in the 27th minute on Saturday before returning to the Spanish capital for tests.
Ronaldo, already ruled out of Portugal's final World Cup Group One qualifier against Malta on Wednesday, looks certain to miss Real's Champions League match against AC Milan on October 21.
"A clinical examination and a scan showed the player had suffered a recurrence of the injury to his right ankle," Real said in a statement on their website. "Estimated time out of action three to four weeks depending on clinical developments."
The Federacao Portuguesa de Futebol (FPF) earlier confirmed the FIFA World Player of the Year would be sidelined as Portugal seek the home victory that will secure a play-off berth. Ronaldo's injury may yet prevent him from playing in any play-off that Portugal may reach.
"After the medical examination and the failure to recover from the injury he has suffered in his right ankle, Cristiano Ronaldo was given permission to leave the Portugal national squad,'' the FPF said in a statement.
"Therefore, the player cannot play the team's next match on Wednesday, October 14, in Guimaraes, against Malta.''
He recovered ahead of the Hungary match, and on Friday told reporters he was almost fully fit, but the injury forced him off after just 30 minutes in the Ferenc Puskas Stadium.
The 24-year-old had made an impact before his departure as his shot in the 18th minute was fumbled by keeper Gabor Babos and Atletico Madrid winger Simao reacted quickest to tuck away the loose ball and set his side on their way to victory.
The Real Madrid star was then replaced by former Manchester United team-mate Nani.