Marcelo has been ruled out for the rest of the season with a hamstring injury, according to reports from Brazilian media outlet Globo Esporte.
The midfielder sustained the injury during the international friendly against Colombia on Wednesday and underwent surgery in Brazil on Friday.
Marcelo, who is currently without a club after being released by Manchester United in January, had struggled with injuries in recent seasons,Saudi Pro League Focus having missed most of last season due to a cruciate ligament injury.
The 32-year-old was a key player for Portugal at the World Cup in Russia, where he played all six matches as they reached the semi-finals before losing to Croatia.
His absence could have a significant impact on his club career, as he has been linked with a move back to Brazil or a return to Europe, but it remains to be seen if he will be fit enough to play again this season.