Lionel Messi will miss PSG's away game at Metz after picking up a knock to his left knee, the club have confirmed.
Messi underwent an MRI scan which confirmed the signs of bone contusion. A further update regarding his fitness will be released in the next 48 hours.
PSG host Montpellier on Saturday before they face Manchester City in the Champions League on September 28.
Ramos backs Messi for Ballon d'Or: I wish him all the luck in the world
Messi was substituted by manager Mauricio Pochettino in the 76th minute during his home debut against Lyon on Sunday.
The decision appeared to frustrate the 34-year-old Argentine who did not shake hands with his boss when he left the pitch.
Pochettino defended his decision after the match. He said: "Sometimes it pleases people, or it doesn't. I asked him how he was, and he said he was fine."
- Parker: Chelsea's midfield makes them Premier League title favourites
- Martial given green light to look for move, Arsenal linked to Jovic - Transfer Notebook
Messi is yet to score so far in his three PSG appearances.
PSG currently sit top of the Ligue 1 table on 18 points after six matches, five points ahead of second-placed Marseille.
Marco Verratti is back in training while Sergio Ramos - who is still yet to make his PSG debut after moving from Real Madrid in the summer on a free transfer - is training individually as he steps up his recovery.
Ballon d'Or live - Messi in battle with Lewandowski for top award
Ronaldo's 'ambition' is to win more Ballon d'Or awards than Messi - France Football boss