Real Madrid forward Kylian Mbappe is in hospital with gastroenteritis after missing their Club World Cup opener against Al-Hilal.
Real drew 1-1 with the Saudi side in Philadelphia on Wednesday, with the club saying Mbappe was missing through illness.
But they said on Thursday that he has “acute gastroenteritis” and is in hospital for “various tests and treatment”.
Gastroenteritis is an infection in the gut which causes vomiting or diarrhoea.
Head coach Xabi Alonso refrained from going into medical specifics about Mbappe’s condition, but the Real Madrid boss acknowledged that the striker had been struggling in recent days.
He said: “I don’t know if Mbappé will be back for the next game. We’ll see. He wasn’t doing well in the last two days. He’s sick.”