Neymar and Mbappe are both trying to recover from injuries in time for the Champions League clash with Liverpool, the club said on Wednesday.
PSG said a scan had showed that Neymar strained an adductor muscle in his groin in Brazil’s 1-0 friendly win against Cameroon on Tuesday.
And Mbappe has a shoulder contusion after falling heavily in France’s 1-0 win over Uruguay at the Stade de France.
“A 48-hour period of treatment will be undertaken to assess their clinical evolution,” PSG said.
It is likely that both players will miss PSG’s Ligue 1 match against Toulouse on Saturday, and hopefully be available for Wednesday’s Champions League match against Liverpool at the Parc des Princes.