Marcus Rashford has struggled for game time under Jose Mourinho
Rashford burst onto the scene last season with nine goals after Louis van Gaal handed the 19-year-old his senior debut in February.
But the England international has struggled for game time under Mourinho, starting just 10 Premier League matches this season.
Marcus Rashford has fallen behind Zlatan Ibrahimovic in the pecking order
He's also been playing out of position on the flanks, with leading goalscorer Zlatan Ibrahimovic favoured in the centre of attack.
But former Red Devils defender Brown is confident Rashford will get the chance to prove his worth to Mourinho at some point this season.
"It is hard," Brown said of Rashford's situation at Old Trafford.
Marcus Rashford and Harry Kane team up with European stars to launch Nike boots
Tue, January 17, 2017
Marcus Rashford and Harry Kane have linked up with several European stars to help launch Nike's new Hypervenom boots
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Marcus Rashford and Harry Kane have helped launch a new line of Nike boots
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"I remember when I got through, it is 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.
"It is 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. But he is young and I am sure Mourinho has got him in his plans for the future."