Neymar was stretchered off from PSG's win over rival Marseille.
Neymar faces a race to be fit for the second leg of Paris Saint-Germain's Champions League last 16 tie against Real Madrid after he was stretchered off against Marseille in Sunday's Classique.
The world's most expensive player appeared to roll his ankle in the Ligue 1 clash, which PSG won 3-0 thanks to goals from Kylian Mbappe and Edinson Cavani, and manager Unai Emery hinted that the Brazilian could struggle to return in time for next Tuesday's game.
"The first tests we have done show it is a sprain, we will do more medical examinations to be totally sure," he said after the match. "Neymar is going to do some new tests. We’re going to stay optimistic. If today I had to say yes or no to be fit against Real [Madrid], I would say yes. I want to be optimistic."
The French league leaders go into the second leg of their tie against the defending champions trailing 3-1 after a fiery match at the Bernabeu, Zinedine Zidane's men coming back from 1-0 down to put themselves in the driving seat against one of the most expensively assembled sides in history.
The €222m man, Neymar is a major part of that side, with 28 goals and 16 assists in just 30 games this season - including six goals and three assists in his seven Champions League appearances.
PSG goalkeeper Alphonse Areola admitted after the game: "Of course, I'm worried about Neymar. His ankle was pretty swollen. He is an important player for us and I hope he will come back soon. I do not know much more, there were a lot of people around him."