Co-owners INEOS have constructed a new senior leadership team over the summer as they look to support manager Erik ten Hag.
Sir Jim Ratcliffe has brought in chief executive Omar Berrada from rivals Manchester City, sporting director Dan Ashworth, and technical director Jason Wilcox in a bid to transform the club.
United alsoappointed Sam Erith, who has worked at both England and Manchester City, as their new performance director on an interim basis just last week.
And now Armstrong looks set to leave PSG to make the move to the northwest of England, according to L'Equipe.
According to reports, Man United are closing in on PSG director Marc Armstrong (centre)
The British director joined the French champions in 2018, taking up the role of chief partnerships officer, before being promoted to his current role in 2022.
During his time in the French capital, Armstrong worked with Jean-Claude Blanc, another director that has been snapped up by United as part of Ratcliffe's overhaul.
The Brit started his career with the Football Association in 1997, spending 10 years at English football's governing body as Head of Business Development.
Armstrong has also held commercial and marketing roles at both the NFL and NBA before entering the world of club football six years ago.
United's transformation behind the scenes has shown no signs of slowing down as deputy football director Andy O’Boyle left the club earlier this month.
Just as the Red Devils' team of directors looks set to grow further, the 20-time champions of English football released their latest financial accounts.
In a statement, Berrada stated that United are striving for 'greater financial sustainability' and to do this they are 'making changes' to their operations.
It seems one of those changes could be the acquisition of Armstrong, who looks on the cusp of a return to his motherland.