Ferguson, who turns 71 on New Year's Eve, is yet to put a date on retirement but it is widely expected to be before his 75th birthday.
The club, though, admit that they are aware of how they will go about replacing Ferguson - but vice-chairman Ed Woodward insists they will not even look at the plan until they need to.
"We have a view as to what type of manager we want and how and when we'll go about it," he is quoted by The Sun.
"But it's in the drawer and long may it stay in the drawer." Woodward, who has already insisted the club's owners the Glazers intend to keep control of United for many years, stressed that money would always be available to bolster the squad.
He said: "Every single player Sir Alex Ferguson has wanted to buy he has been supported. Some have slipped through our fingers but we have never said that we cannot afford a player. Robin van Persie is a good example; one of the best players in the world and we easily had the financial capacity to do that.
"We have a pretty low level of leverage. Interest payments of £31million leaves a significant amount of money, around £76million and we decide what we do with that.
"We are very comfortable about the ability to fund the interest and there will be more income growth next year from the new Premier League media deal."