According to Corriere dello Sport (h/t Sport Witness), United manager Jose Mourinho is keen to bring Mario to the club with the coach initiating discussions about a potential deal.
In the report it's suggested Inter would wait for an offer of around €45 million (£40 million) before agreeing to any sale. However, another option is said to be being considered, with United potentially ready to take Mario on loan.
It's added that Mkhitaryan would head the other way as part of this loan exchange so they can "try out" life at a new club ahead of possible permanent switch.
As things stand, it's the type of deal that'd make sense for both players, as neither have been able to muscle their way into contention for regular first-team starts this season. For Serie A leaders Inter, Mario has only started four top-flight matches.
WhoScored.com's Cristiano Acconci believes Inter could be doing more to get the best out of the Portuguese midfielder:
When Mario arrived at Inter in the summer of 2016 he was deemed to be a major signing for the San Siro side.
In his debut term inconsistency blighted his game, as Inter went through different managers and the midfielder was asked to fulfil a number of different roles in the side. While manager Luciano Spalletti has added some crucial continuity to the Nerazzurri this term, it appears as though Mario isn't part of his plans.
The same could be said for Mkhitaryan at United who, after a good beginning to the season, has quickly fallen out of favour at Old Trafford. As noted by James Ducker of the Daily Telegraph, the player is in a difficult situation with the Red Devils:
The Armenia international was on fire earlier in the campaign, grabbing five assists in the first three Premier League games. However, his form has nosedived, and his last start for the team in any competition came on November 5 in the defeat to Chelsea.
Per Samuel Luckhurst of the Manchester Evening News, it appears as though the 28-year-old is at least working hard to win his place back in the side:
Neither man will be content with his current situation, so the change midseason may rekindle the obvious talent both midfielders have.
If United were able to get Mario it's easy to see him thriving under Mourinho. Aside from being technically gifted and versatile, there's a grit to the Inter star's game that could appeal to the United boss. It's easy to see him linking well with the dynamic threats the Red Devils boast in Romelu Lukaku, Anthony Martial and Marcus Rashford.
Still, based on what he's shown in glimpses for the team, there will be plenty tied to the Old Trafford outfit unwilling to give up on Mkhitaryan quite yet.