The 23-year-old has been earning rave reviews in Serie A this season, with many proclaiming the Albanian to be the best right-back in the league since leaving Empoli for the Stadio San Paolo in a €5 million move in 2015.
And as they prepare to make long-term decisions relating to Matteo Darmian and Luke Shaw, Jose Mourinho’s outfit have been extensively scouting Hysaj ahead of a potential approach in the summer, Goal can reveal.
Darmian has slipped down the pecking order at United since his arrival at Old Trafford under Louis van Gaal in 2015 and is expected to be offloaded this summer. Meanwhile, Shaw has played just twice in four months across all competitions after failing to prove to Mourinho that he has the mental attitude the Portuguese requires of him.
A third full-back, Ashley Young, could also be on his way out after the 2016-17 season after making just five starts since turning down approaches during the January transfer window.
The result is that while Antonio Valencia has locked down the right-back slot, there is a lack of depth in Mourinho’s stocks at full-back. And Hysaj’s ability to play on the left side of the defence as well as the right is a huge selling point.
Hysaj might not come cheap, with Maurizio Sarri’s outfit having inserted a buyout clause worth €50m (£42.7m) into his contract, but his proven quality at the top of the Italian game could persuade United to do a deal.
United also have Daley Blind and Marcos Rojo as left-back cover, while Timo Fosu-Mensah is available to play on the right. But Mourinho is keen to add quality higher up the pecking order, hence the interest in bringing Hysaj to Old Trafford.
The 29-cap Albania international has so far made 76 appearances in his two seasons at Napoli.