Paris St Germain forward Lionel Messi and three other players have tested positive for COVID-19.
Argentina international Messi, 34, joined PSG from boyhood club Barcelona in August and has scored six goals in 16 games in all competitions for the Parisian side.
Defender Juan Bernat, back-up goalkeeper Sergio Rico and midfielder Nathan Bitumazala are the other players who have returned positive tests.
PSG says the four players are in isolation and subject to the appropriate health protocols.
Mauricio Pochettino's team are atop the Ligue 1 standings on 46 points after 19 matches, 13 points above second-placed Nice.
They are due to travel to third-tier club Vannes for a French Cup round-of-32 match.
Pochettino is unsure if Messi, who is currently in Argentina, will feature in their next league game at Olympique Lyonnais on January 9.
"Messi has been in regular contact with our medical team and when he has a negative test, he will travel to France, but we don't know any more than that," says the former Spurs manager. "I don't know if he will be involved against Lyon.
"Until he gets a negative test in Argentina, he will not be able to travel to France, so it is all down to the test in terms of when he can travel - we will assess when he is ready to play."
France reported 219,126 new confirmed COVID-19 cases in a 24-hour period on Saturday, the fourth consecutive day of more than 200,000 cases.
France has joined the United States, India, Brazil, Britain and Russia with more than 10 million cases.