The 40-year-old Italian will be in goal for PSG on Wednesday when it travels to play Napoli, where a loss would be a huge blow to the team's chances of advancing from the group stage of the Champions League.
It is exactly the type of high-pressure game which PSG signed Buffon for, although not this early. No doubt the club's cash-rich Qatari owners were hoping Buffon would be making his trademark saves in the semifinals or the final.
PSG has not been past the quarterfinals since QSI took over in June 2011. The team has only four points from the first three group games and still has to face group leader Liverpool.
The atmosphere in the southern city of Naples is likely to be hostile, in particular for Buffon as a former Juventus player. Napoli's passionate tifosi will reserve a vitriolic reception for the goalkeeper, but he has seen and heard it all before.
PSG coach Thomas Tuchel will certainly hope so, anyway, for he is facing the embarrassing prospect of becoming the first PSG coach not to qualify from the group stage since the vastly ambitious QSI took over seven years ago.
Tuchel has two very good goalkeepers, but clearly he has designated Buffon as first choice ahead of Alphonse Areola by picking him for Napoli. Areola played in the first three group games while Buffon was suspended.
The 25-year-old Areola is a homegrown player who has done well to force his way in at PSG.
He was particularly impressive in his France debut, making some spectacular saves in a 0-0 draw at Germany in the UEFA Nations League in September, and is unlucky in a sense that PSG signed Buffon.
But it is also true that, for such a high-pressure game, he simply does not have the stature as Buffon. Nor does he offer the immensely reassuring presence Buffon does.
Buffon has been Serie A goalkeeper of the year 12 times, including the past four seasons.
"He has a very important role for us because he's a legend. He's very important for us in terms of his approach to the sport," said Tuchel, who as a coach favoring a big work ethic could hardly have a better example than Buffon for his players to look up to.
A World Cup winner with Italy in 2006, Buffon made 656 appearances for Juventus and 176 for Italy. He was expected to retire after winning a seventh straight Serie A title, but then PSG came calling and he took up the challenge of moving to a new league at an advanced age.
"It's very important that he's here and that he talks with everyone to share his experience," said Tuchel, adding that Buffon will be in goal for Friday's home game against second-place Lille.
Earlier this season, Buffon showed that he has lost none of his sublime reflexes, making an astonishing save against Guingamp in a league game. Buffon looked beaten by striker Nolan Roux's shot as he dived to his left, but the Italian veteran showed astonishing agility to stick out his right hand and push the ball off the crossbar. It was a world class save few can do, but the type of save Buffon often does.
The only thing missing from Buffon's glittering career is a European Championship title — Italy lost the Euro 2012 final — and a Champions League title after losing in three finals with Juventus.
Buffon will need a big performance against Napoli to keep that dream alive, which bodes rather well for PSG.