Former Manchester United manager Tommy Docherty believes Sir Alex Ferguson will be allowed to choose his own successor and is likely to select Everton boss David Moyes.
"Fergie will make the appointment of whoever takes his place, not the directors," Docherty told BBC Sport.
"I think it will be David Moyes because they are good friends. He's done a great job at Everton with no money."
Ferguson said in February he wanted to continue for "two or three more years".
Docherty, who managed United between 1972 and 1977, says replacing a man who has won 12 league titles and two European Cups in 25 years at Old Trafford is "an impossible task".
But he believes Moyes, who on a shoestring budget has led Everton to four top-six finishes in 10 years, has the attributes to take on the challenge.
"If I was a gambling man I would say David Moyes," said Docherty. "He's an ex-player, but not a great player, just as Sir Alex wasn't a great player, but their records as managers are fantastic.
"Alec will probably move upstairs, but he will want a new manager who knows how the game is played, how the club should be run and keep in contact with him about what's going on."
Ferguson almost retired in 2002 but changed his mind, and Docherty believes the 70-year-old could well go on beyond the three years he mentioned in an exclusive interview with BBC Radio 5 live Sport.
"I think he will carry on managing Manchester United as long as keeps his enthusiasm and his health," said Docherty.
"If he does that that there's no reason he can't carry on for I don't know how long."