The Englishman is set to get his first start in three games in the FA Cup fifth round at Ewood Park this weekend as Man United face Blackburn.
Brown, who could be on the bench for the Championship side, has shared his thoughts on how hard it can be for a youngster to graduate into a first-team regular at Old Trafford.
Speaking about Rashford’s situation, Brown has warned him he has to take his chances when they come.
“It’s hard. I remember when I got through, it’s not as bad as this, but you know you have got a couple of games to show what you can do otherwise you get dropped back again,” he said.
“It’s not the end and he has obviously done fantastic. At the moment he has not played that much, he has come on as a sub.
“He is young and I am sure Mourinho has got him in his plans for the future.”
While Brown may believe it’s hard to graduate into a first-team regular, Rashford has done just that, racking up 50 senior appearances in just under a year since his debut.
He’s showcased his incredible talent on the main stage and Mourinho understands that the Englishman has a wonderful future ahead at Old Trafford.