Lionel Messi, who came to PSG this summer from Barcelona, has had a tough season where he did not really live up to expectations.
In 26 games, the striker has scored seven goals, compared to last season in Barcelona when he scored 38 goals.
Now Messi misses the chance to improve his statistics as he became ill and missed today's match against Monaco.
It is a hospital in PSG and several other players also miss the match.
The team lacks players Keylor Navas, Sergio Ramos and Angel Di Maria in the match.
PSG leads the French league by far and is on its way to the club's tenth league title.
The team is 15 points ahead of runner-up Marseille.