PSG will be without its star man, who sustained a metatarsal injury late last month, for both legs of the last-16 tie. The Brazilian international is expected to return in April.
And the 41-year-old Buffon, who has reached the final of the competition three times but has yet to win the Champions League during his illustrious career, is wary of facing an in-form United without the Brazilian.
“I think this is a problem for us,” PSG goalkeeper Buffon told CNN in an exclusive interview ahead of Tuesday’s first leg at Old Trafford.
“I’m not sure if it’s a big problem or a little one. I hope it’s only a small problem and that we are nevertheless a team that can thrive without him, it would give us great strength and confidence.
“But I must say that without a player of Ney’s caliber, it’s going to be heavy going, particularly because in the last two or three months he’s in excellent condition both physically and mentally and would have been of enormous help.
“But nevertheless we have to do our best in order not to have any regrets and play the quarterfinals and semifinals with Ney back.
“This would be the best present we could give to him, and I’m sure he would return the favor by playing in those two matches.”
PSG faces a tough task to make it past United with the English Premier League team having been transformed by Soskjaer since he replaced former boss Jose Mourinho in late December.
United has won 10 of their 11 games under the Norwegian and have surged into fourth place in the Premier League.
The France World Cup winning star has scored 18 league goals so far this season as well as three in the Champions League.
For Buffon, who left Juventus last July after 17 years with the Italian club, the opportunity to work with young players such as Mbappe was a huge draw.
The two enjoy a close relationship with Buffon keen to pass on his experiences to the prodigious young talent, even if Mbappe cheekily refers to him as “grandpa.”
“It’s only normal that Kylian, who is 20 and thinks of me as a father figure or even a grandpa, but I think that’s nice,” Buffon said.
“I’ve experienced so many wonderful things in my career. Firstly as a young, adolescent cocky player who was surrounded by older players and my mission then was to be accepted by them.
“Then as a young man, and lastly as an older man who meets a young man who was just like me when I was the same age.
“This is all part of the difficulties of life, and you understand how different people’s opinions are, and by changing your point of view over time you see how things can be different. But I must say it’s all part of the rich fabric of life.
“And when I joke about with Kylian we have a friendly rapport and it feels like we’re the same age. The way I see it, we have to find common ground and I have to act in a younger way and he has to think along the lines of someone slightly older perhaps.”
While Mbappe may have several more opportunities to win the Champions League, Buffon’s future is more uncertain.
Though wholly committed to the club until the end of the season, the 41-year-old remains unsure of how long he will play on for.
“I don’t know,” Buffon, who signed a one-year deal and has an option for a further 12 months, said when asked about his future.
“The opportunity may well present itself, but nothing has been carved in stone. I think that a player like me and of my age shouldn’t make long-term plans.”