The biggest problem for him is at 21 years old he is expected to behave and be one of the senior players, that's just plan wrong.
In one of his recent post match interviews he spoke of 'the youngsters coming through' and it's 'good to see the development of the youth players'. He is still a youth player.
The balance of youth in the squad has tipped too far to the point we are putting heavy expectations on players who shouldn't be in that position. Add to that the complete lack of quality (Matic, Mata, Young, I could go on) or attitude (Lingard, Pogba) in our senior players and there is ridiculous pressure put on Rashford's shoulders to perform every week.