Indeed, according to Sport, Manchester United are weighing up a huge summer move for Umtiti by meeting his £54m release clause.
Sport also reports that Umtiti is "letting himself be loved" by Mourinho, who has ordered his French national team-mates Paul Pogba and Anthony Martial with charming him to Manchester.
The 24-year-old defender has become a crucial player for the Catalan side since arriving from Lyon in the summer of 2016, forming an impressive partnership alongside Gerard Pique in the heart of defence.
Yannick Umtiti, Samuel's brother and agent, is said to be in contact with officials from Old Trafford, and it is claimed the centre-back would be willing to make the move after speaking to Mourinho on several occasions.
And, the club are prepared to offer what Sport state as a "stratospheric" salary offer, with the Red Devils putting together a €9m-a-year package, more than double his €4m-a-year wage at Barca.
His form has sparked interest from across the continent - so too the £50m release clause on his current deal at the Spanish league leaders.
SPORT add Barcelona are convinced they will get the approval from Umiti that he will stay, but they want him to lower his demands.
According to the same story, Mourinho is a "big fan" of the 24-year-old France global, who has made 19 La Liga appearances for FC Barcelona so far this season.