Brazilian forward Neymar was substituted in tears after suffering what appeared to be a right ankle injury as Paris St Germain (PSG) beat Racing Strasbourg 2-0 on Wednesday.
The Brazil striker left the pitch after an hour in a French Cup last 32 game after receiving a knock and twisting his ankle.
His injury has come three weeks before PSG travel to Manchester United for their UEFA Champions League last 16 first leg fixture.
PSG, who are runaway leaders in Ligue 1, are already sweating on the fitness of key midfielder Marco Verratti, who is suffering from an ankle injury.
Thomas Tuchel’s side prevailed at the Parc des Princes, thanks to a goal in each half from Edinson Cavani and Angel Di Maria.
Elsewhere, St Etienne slumped to a 6-3 home defeat to Dijon.