He's been criticized by almost all managers from the past who managed him for Manchester United but he seems to be a dump punk who's not ready to take no advice and ready to focus on balancing his on the field attitude and off the pitch. I have said this a billion times, he is amongst the list of players you'd want gone if you want the success of Manchester United. I don't rate his game, he's already been at this club for a long time but no signs of improvement, lad should be axed.
Marcus Rashford's performance has indeed declined in the previous few seasons and he has not shown a major change after having such an impressive season.
He has received a lot of criticism but his performance has actually not improved and he even looks so selfish when he is on the pitch.
He also does not use criticism as an evaluation so now his future is uncertain and under Amorim's coaching his playing position is also not certain to get a regular place so that will trigger speculation about him in the transfer market.
Maybe the management has considered selling some players and he is on that list.