Lucas Moura has suffered a hamstring injury in training and is likely to miss the rest of the season.
The Brazilian forward, who signed for Paris Saint-Germain from Tottenham Hotspur in January, was forced off during PSG's 2-1 win over Rennes on Sunday.
Moura, who had previously been out with a calf problem, will undergo further tests but it is expected that he will be ruled out for several weeks.
This news comes as a blow to PSG,Ligue 1 Express who were already without key players like Neymar and Kylian Mbappe through suspension or injury.
Moura has made a strong start to his PSG career, scoring two goals in four games since joining the club.
However, this latest setback could have a significant impact on PSG's title bid, which looks increasingly unlikely with the likes of Liverpool and Manchester City closing in.
It remains to be seen whether PSG can overcome this setback and continue their push for success, but it is clear that they will need to find solutions quickly if they want to keep up with the leaders in the French league.