The pair were forced off with knocks during Brazil and France's respective friendlies during the international break.
The severity of Neymar and Mbappe's injuries had already been played down but PSG have since issued an update to confirm the knocks are not serious.
However, the Ligue 1 champions have revealed the star duo will undergo a period of treatment before determining whether they will be fit to face Liverpool on 28 November.
PSG confirmed in a brief medical statement that Neymar has been diagnosed with "a right adductor strain", while Mbappe has "a bruised right shoulder".
"They will undergo a 48-hour period of treatment before further evaluation," the club's update added.
Brazil still managed to win 1-0 thanks to a goal from Richarlison, who replaced Neymar, whereas France edged Uruguay by the same scoreline after an Olivier Giroud penalty.
PSG will put their 100 per cent league record on the line when they host Toulouse at the Parc des Princes on Saturday.
Thomas Tuchel's men have won all 13 of their league matches so far, opening up a remarkable 13-point lead over second-placed Lille.
However, they are not as comfortable in the Champions League and their upcoming game against Liverpool will be pivotal in deciding who will reach the knockout phase.
PSG are currently third in Group C and a point behind both Napoli and Liverpool with just two games remaining in the group phase of Europe's premier club competition.
They host last season's beaten finalists Liverpool before locking horns with Serbian outfit Red Star Belgrade in their last pool fixture on December 11.
Neymar and Mbappe have been lethal for PSG so far this season, scoring 13 goals apiece in all competitions.