Italy forward Moise Kean, 20, joined on loan from Everton just before the transfer window shut earlier this month.
He appeared as a substitute for Italy in their Nations League draw with the Netherlands on Wednesday but is still likely to be fresher than Mbappe, who played all of France's 2-1 win in Croatia and scored the winner.
Meanwhile, Neymar scored a hat-trick in Brazil's 4-2 win in Peru in 2022 World Cup qualifying. That match in Lima did not finish until the early hours of Wednesday, European time.
PSG, whose start to the new season has been disrupted by injuries, suspensions and coronavirus cases, are also without Mauro Icardi due to injury for this weekend's Ligue 1 game at Nimes and the meeting with Ole Gunnar Solskjaer's side on Tuesday.
With Angel di Maria suspended, and a host of other players missing, PSG coach Thomas Tuchel could certainly do with Kean in Nimes, even if the former Juventus player only arrived in the French capital on Thursday following international duty.
Of PSG's other recent signings, midfielder Danilo Pereira must wait for his debut after arriving on loan from Porto -- he is isolating after coming into contact with Cristiano Ronaldo, who tested positive for Covid-19, while on international duty with Portugal.
However, Rafinha is available following his arrival from Barcelona.
"Rafinha has been training with us for 10 days and he's a very technical player, very humble and very easy to get on with," said Tuchel.
"I know he'll be able to adapt quickly and of course he'll be able to play. Kean could also play his first match for us, we will talk with him when he arrives and he'll have a training session, and it's possible he'll play."
Around 5,000 fans will attend the game in Nimes, but other matches in France this weekend will be impacted by the government's introduction of a curfew in Paris and eight other cities as it tries to bring the ongoing coronavirus outbreak under control.
Residents where the curfew is in place will not be allowed to be outdoors between 9:00 pm and 6:00 am from Saturday, for at least four weeks, except for essential reasons.
That means Marseille's home game with Bordeaux on Saturday, and the derby between Lille and Lens on Sunday, will be behind closed doors.
Player to watch: Hatem Ben Arfa
The great maverick Ben Arfa is back in France after signing an initial one-year deal with Bordeaux. The 33-year-old attacking midfielder was a free agent after leaving Spanish side Valladolid.
Capped 15 times by France, Ben Arfa has blown hot and cold throughout his career: a fabulous talent as a youngster at Lyon, he showed flashes of genius in England with Newcastle United and had a wonderful year at Nice in 2015/16.
However, a subsequent move to Paris Saint-Germain did not work out and he struggled to make an impression last season in Spain.
He could make his Bordeaux debut on Saturday at Marseille, another of his former clubs.
24 - PSG's budget for last season was understood to be 24 times greater than that of Nimes, whose own budget was the smallest in Ligue 1.
6 - Senegalese forward Ibrahima Niane of Metz is Ligue 1's leading scorer having scored all his side's six goals. However he is now set to be out for several months after suffering a serious knee injury.
9 - Leaders Rennes are unbeaten in nine league games before taking on Dijon on Friday.
Fixtures (Kick-offs GMT)
Dijon v Rennes (1700), Nimes v Paris Saint-Germain (1900)
Reims v Lorient (1500), Marseille v Bordeaux (1900)
Strasbourg v Lyon (1100), Angers v Metz, Monaco v Montpellier, Nantes v Brest (all 1300), Saint-Etienne v Nice (1500), Lille v Lens (1900)