The United hierarchy are said to be concerned by Louis van Gaal's pessimistic appraisal of the club's top-four chances.
But could a Mourinho appointment have terrible consequences for Manchester City... and Pep Guardiola?
Van Gaal's negative attitude suggests he has given up on a Champions League place next season but Mourinho will bring a new energy to Old Trafford.
Assuming this is the Mourinho who has won Champions League and Premier League titles, not the man who crumbled under the spotlight at Chelsea earlier this season, United could easily pounce on Manchester City's weak position before the end of the season.
Manchester United are just six points behind City with 12 league games left this season. And just look at Manuel Pellegrini's side. Big game after big game, they are crumbling. They don't look interested.
Mourinho could capitalise - and steal fourth spot from under City's noses. That would leave Guardiola without Champions League football during his first year at Manchester City - and leave Manchester United fans very satisfied indeed.