Neymar will have tests on Monday on the suspected broken ankle he suffered during's Paris-Saint Germain's defeat to Lyon on Sunday.
The Brazilian star left the pitch in tears as he was stretchered off in the dying moments of the Ligue 1 clash at the Parc des Princes.
He suffered what looked like a serious ankle injury following a late challenge from Thiago Mendes, with videos appearing to show the joint could be broken.
PSG now face an anxious wait to discover how serious the injury is, and how long the 28-year-old forward will be out of action.
Boss Thomas Tuchel confirmed afterwards that Neymar would have tests on Monday to determine the severity of the injury.
"He's with the physio and the doctors and we have to wait for the tests tomorrow (Monday)," Tuchel told French broadcaster Telefoot .
Tino Kadewere had scored the only goal in the first half as Lyon leapfrogged PSG into second place, with the reigning champions dropping into third.
Lille went top following their 2-1 victory at home to Bordeaux.
Marseille are just a point behind PSG in fourth place, and have two games in hand over all three of the sides above them.
But Neymar's injury will be a bigger worry for Tuchel than his side's current league position.
The former Barcelona ace has had rancid luck with injuries while at PSG, but this one could be the worst of the lot.
During his time in Paris, the Brazil international has fractured his metatarsal on two separate occasions.
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He also missed the Copa America in 2019 after rupturing ankle ligaments.
Neymar signed for PSG in 2017 but his injury history has meant he has played just 58 times for the French giants.