United have held talks with representatives of former Chelsea boss Jose Mourinho ahead of the match between the two sides at Stamford Bridge on Sunday.
The 53-year-old, whom left Blues for the second time in December, is a known admirer of the Old Trafford outfit and is increasingly hopeful of succeeding Louis van Gaal in the United hotseat.
No agreement has been reached and neither party have commented, but negotiations have begun and it looks increasingly likely that van Gaal is to leave the club in the summer- one year earlier than originally planned.
That would leave the way clear for the Portuguese, with Mourinho said to be excited at the chance of his long-held ambition to take over at United.
The club's hierarchy are thought to be keen to respond after Manchester City secured the services of sought-after former Barcelona coach Pep Guardiola earlier this week.
Mourinho's arrival would mean a resumption of a rivalry that began in Spain when he was manager of Real Madrid between 2010 and 2013.
It has been widely assumed that the most obvious alternative to Mourinho is our most decorated player and current assistant, Ryan Giggs.
Giggsy took the team for a four-game stint at the end of the 2013/14 after the sacking of David Moyes, and it would be a surprise were he not interested in replacing the Dutchman on a full-time basis.
Giggs is unwilling to take the job on a temporary basis and, having been happy to further his coaching education under Van Gaal, it remains unclear what would happen with Giggsy should Mourinho arrive.
Twice in recent weeks, Van Gaal's tenure has been perilous and left support for Mourinho growing.
Defeats by Stoke on Boxing Day and at home to Southampton last month appeared to left the Dutchman on the brink, but have been followed by an upturn in results and performances.
However, despite the improvement the club are still open to making a change in the summer and although nothing is yet confirmed, it would appear these developments could be the beginning of the end for Van Gaal.
City have reportedly already lined up a number of big name signings to join Guardiola across town and the club believe the arrival of the self proclaimed Special One will put us on a level playing field.
Mourinho was considered the favourite to take over from SAF in 2013 but had already agreed to go back to Chelsea.