The Naples side encountered a sudden boost in financial power earlier last week after selling Gonzalo Higuain to Juventus for €90m.
Darmian left Serie A side Torino for Old Trafford last summer. Following an excellent start to his Man United career, the Italian regressed as the season went on.
But following a strong set of performances at Euro 2016, Napoli are prepared to make use of their new financial wealth in order to lure Darmian back to Italy.
The 26-year-old would have been immensely disappointed with the way his debut season in England materialised, especially after such a strong start. On his debut, the Italian took to the field with a tangible air of assurance and discipline, mopping up any threats and offering support in attack in a Man of the Match performance against Tottenham Hotspur.
Positive performances continued until, like so many in the squad, he began to feel inundated by Louis van Gaal‘s cautious approach, disappearing as the season wore on. But under Mourinho, the Italian has a fantastic chance to rectify the explosive form he displayed last year. Darmian will feel that he has a point to prove at Old Trafford next season, and isn’t the type to jump ship after one unsuccessful campaign.