Manchester United looks to have been alerted amid speculation that Jose Mourinho has been given the option of returning to Real Madrid, Mirror reports.
The recently sacked Chelsea boss was in charge of the La Liga champions before making his return to Stamford Bridge.
He left Real two-and-a-half years ago after a number of issues with the players as well as the fans, but is said to still be on the good side of club president Florentino Perez, who is keen on his return.
United boss Louis van Gaal is under heavy pressure to perform after picking up three consecutive Premier League losses against Bournemouth, Norwich City, and most recently Stoke City.
It is now said that the Red Devils board are considering a move to bring in Mourinho to replace Van Gaal should they fail to beat his former side in their upcoming match ahead of the New Year.
The former Blues manager will now have to decide if he should wait for the job at Old Trafford or make another attempt to impress at the Bernabeu.