However, the centre-back is merely using the offer on the table to negotiate a better deal with Barcelona.
His latest all-conquering display in Barca's 1-0 win over La Liga title rivals Atletico Madrid only further enhanced his reputation, with him and Gerard Pique expertly marshalling Antoine Griezmann and Diego Costa.
Mourinho is also said to be recruting fellow French players Paul Pogba and Anthony Martial as a means to tempt Umtiti into moving, although he already has compatriots Ousmane Dembele and Lucas Digne for company.
However, it would be similarly unsurprising if United were interested in a 24-year-old who has made 30 appearances for one of Europe's top clubs this season in defence, missing games only for a muscle injury and occasional suspensions.
Dejan Lovren tussles with Romelu Lukaku during the game
Although it seems unlikely he'd be tempted to leave the Camp Nou for Manchester, the same report claims Mourinho has called him regularly to try and persuade him to make the move, using global teammates Anthony Martial and Paul Pogba to try and sell the club to him.
United would be able to sign him with relative ease should they decide to do so, simply by triggering his €60 million (£53m) buyout clause, a fee similar to what Man City paid for Aymeric Laporte back in January.
As well as coughing up £54m, United would also be willing to offer double Umtiti's wages to £150,000-a-week if he joined.
Talks are underway, and Umtiti wants from the Catalan giants what United are prepared to pay - £8m a year.