It therefore looks like he is running down his contract at Old Trafford and will earn the right to choose his next club for himself.
Darmian is not in Ole Gunnar Solskjaer's plans and did not play in a single minute of United's pre-season games.
The 29-year-old did not even fly out to Australia and the Far East - where the Red Devils put in their most intensive training block - and was similarly left out of the matches against Kristiansund and AC Milan on their return to Europe.
He did appear in a behind-closed-doors game against Blackburn Rovers last week, but his status as a first-team star appears to have gone now.
Darmian made just five Premier League starts for the Red Devils last season and only one of those was under Solskjaer.
The highlight of his United career so far was probably the 2017 Uefa Cup Final in Stockholm, where he started on the left-hand side of defence against Ajax as Jose Mourinho's side won 2-0.
United had been expected to sell Darmian this summer but reports emerged that suggested executive vice-chairman Ed Woodward blocked any moves before last week's transfer deadline.
That hardly mattered as the ex-Torino star had always been likely to return to Serie A - with Italian clubs having until September 2 to complete their transfer business. The defender has continually been linked with moves back to Italy throughout his four seasons at Old Trafford. The Nerazzurri are in need of versatile options to play out wide in Conte's 3-5-2 formation and Darmian now looks set to be reunited with former Azzurri boss Antonio Conte, who handed him the bulk of his 36 national team caps between 2014-16.
Darmian did not feature in Inter's talks with Manchester United for Romelu Lukaku, but he remains a popular option with Conte.