Shockingly, people don't like players who don't seem to be giving their all - and that's exactly what Rashford has been doing. Put it down to Speculative Injury #24 if you want; but it's been the case statistically for two years now.
He has
the biggest luxury role in world football. Nobody - not Neymar, not 36 year old Ronaldo, not 34 year old Messi - has contributed less than Rashford off-ball over the last two years.
He somehow had a game a month ago where he covered less ground than Harry Maguire. Like....how?
He never presses, never tracks back, leaves Shaw 1v1 over and over and over again. He quite literally doesn't even break into a jog out of possession.
He HAS to be productive - hugely so - because he's an outright liability both defensively and in the pressing game.
Don't take it from me though. From Fergie's book:
Same reason I'd be happy for Martial to go. He has similarly poor work-rate - although better than Rashford - but is contributing less to back it up.