Docherty expects Rooney stay
However, Docherty, who managed at Old Trafford for five years in the 1970s, would like to see Rooney stay at the club, adding the fans will forgive him for wanting to leave if he hits top form in the Premier League this season.
"I get a bit annoyed sometimes with clubs saying 'this player is not available at any price', every player in the football league is available for transfer providing the price is right," he told OMNISPORT.
"I think it's a massive job for David Moyes, who is a terrific manager. Probably his choice of words were wrong when he said something to the effect of 'we will need Wayne in case anything happens to Robin van Persie'.
"But I don't think his (Rooney's) position is untenable. I mean for arguments sake say Wayne starts the season for United like he normally does and goes off like a bomb, all of this will be forgotten.
"If he starts in the first-team at the start of the season and he goes off like a house on fire, the supporters will forgive and forget."
While the 85-year-old concedes the former Everton striker could leave, he says he would strive to keep him if he were still in charge.
"Financially United are a very wealthy club so they don't need the money, so they don't have to sell him," he continued.
"But if it becomes a situation where Wayne wants to leave or he puts a request in writing, then providing the price is right he could go.
"I mean personally I would keep him, I think he is a tremendous player, he's a very good professional and he scores goals. And he's two years younger than Van Persie."