Rashford has been out of action for more than a month already. He has not been playing since January when he got a serious back injury.
He has scored 19 goals this campaign and Ole Solskjaer revealed that the forward might return late in 2019-20 season.
Ole Gunnar Solskjaer told UK newspapers: "The scan came back very positive.
"We are not going to rush the things, we will give Marcus the time he needs to recover completely."
"Of course he is eager to make his return, but it will happen after couple of months, probably.
"We can't afford to rush it and we won't rush it, but when he come back we will be stronger and that is going to be a great boost for us."
United are fifth in the Premier League table ahead of visiting Everton on Sunday and they are in the FA Cup fifth round and Europa League last 16.
Ole said that Rashford is eager to return as United chase some silverware this season and he is everywhere.
"He's all around the place, in the dressing room before games, at half-time. He really wants the boys to do well so he can return and play in the Europa League, the FA Cup final," said Solskjaer.