Real Madrid's Belgian forward Eden Hazard and his Brazilian team-mate Casemiro have both tested positive for coronavirus, the La Liga club announced on Saturday.
"Real Madrid informs that our players, Casemiro and Eden Hazard, have tested positive in the Covid-19 tests undertaken yesterday, Friday, in the morning," the club said in a statement.
"All of the other first-team players and coaching staff, as well as the club employees who work directly with the squad tested negative in yesterday's tests.
"Meanwhile, all of them, apart from Casemiro and Hazard, once again tested negative in the antigen tests taken this morning."
Neither player will feature in the side to take on Valencia on Sunday. Nor will they be able to join up with their respective national teams during the coming international window as both are required to go into isolation.
"They're fine. They're not happy with what happened, but mentally they're fine, and physically too," said Real Madrid coach Zinedine Zidane in a press conference on Saturday.
"Casi has a few symptoms but in this difficult situation they are fine. I left them a message, I will speak to them again later. This is something that can happen, and we must accept it.
"There was nothing special, they are responsible people, who pay attention... Obviously, I would have preferred to have them."
It marks another setback for Hazard who missed the start of the season owing to a series of ankle injuries. He only returned to the Madrid line-up for the Champions League meeting with Borussia Monchengladbach on 27 October.
On Monday, ahead of their match against Inter Milan, Madrid announced that Brazilian central defender Eder Militao had also tested positive for coronavirus.