That's according to Roger Torello of Spanish outlet Mundo Deportivo (h/t Charles Perrin of the Express), who reports the two clubs "look set for a straight showdown" with one another and the youngster will be "available for £34 million."
The Brazilian has made just 17 of a possible 25 appearances in Ligue 1, and of those, only 10 have been starts. As the Times' Rory Smith wryly noted, Marquinhos has been used as a substitute to shore up Les Parisiens' defence:
French football expert Andrew Gibney believes the 21-year-old should be playing ahead of the uninspiring David Luiz—who joined PSG from Chelsea for a staggering fee:
Further, per Gibney, Marquinhos has recently hinted he could be set to review his situation this summer if his playing time does not improve over the second half of the season:
As the following video demonstrates, the centre-back is an assured and committed defender:
According to Squawka, he has made 17 successful tackles in Ligue 1 this season, as well as winning 18 headed duels and making 54 clearances, 16 interceptions and nine blocks—all while maintaining an exceptional passing accuracy of 94 per cent.
Both Chelsea and United have need of a new star centre-back, though with captain John Terry set to depart Stamford Bridge this summer, it is the Blues who will be far more desperate to reinforce the position.
Chelsea have already conceded 35 goals this term—more than they did in the entirety of the last—with Terry and Co. seriously disappointing, so even if Terry ended up staying with the Blues, a new signing is clearly needed.
Both sides would be able to offer Marquinhos the assurances of first-team football he needs, so it could be a titanic tussle for his signature.
Should the Blues fail to land him or any of their other top defensive targets, they could have a ready-made player already in their ranks—Andreas Christensen, currently on loan at Borussia Monchengladbach.
However, the Bundesliga outfit want to secure the 19-year-old on a permanent basis. Gladbach sporting director Max Eberl said to German magazine Kicker (h/t talkSPORT): "Our intention is to try and get into talks with Chelsea in the summer. Andreas fulfils everything we've seen in him. And we are delighted that we were able to take him on loan without any ifs and buts."
The youngster has stood out this season and was just named the club's Player of the Month for January:
One of his best performances of the season came on Friday, in which he bagged a brace. Bundesliga expert Archie Rhind-Tutt felt his form merited the reward and ran the rule over the Dane:
His reading of the game in particular has belied his years. According to Squawka, he has won an outstanding 45 aerial duels and made a staggering 53 interceptions in just 17 Bundesliga appearances.
Though Christensen has shown enough to warrant a place in Chelsea's squad next season, it wouldn't be at all surprising if the Blues allowed him to slip through their fingers.
Indeed, the Daily Telegraph's Matt Law questioned the decision to sign New York Red Bulls youngster Matt Miazga when Christensen makes a strong alternative:
Christensen has a bright future ahead of him, but he may well be the latest in a long line of exceptional youngsters let go by Chelsea—a list that includes Kevin De Bruyne, Daniel Sturridge and Romelu Lukaku.