Despite having secured a second-place finish in the Premier League, boss Jose Mourinho has come under scrutiny for publicly criticising several members of his own squad.
Pundit Merson told 'The Debate' on 'Sky Sports': ''Every time a Manchester United player misses a chance they always run back and look at Mourinho in the dugout - they look petrified.''
''You watch Manchester City, Tottenham, Chelsea and Liverpool play - and sometimes Arsenal - and you can see the patterns of their attacking play.''
''It looks like there is a plan. It's different at Manchester United - everyone is standing still, everyone just passes the ball - there is no movement. I think the players are petrified.''
Given that there will likely be heightened transfer activity at Old Trafford in the summer, Merson is convinced that several players will be itching to depart the club.
He said: ''If a player gets sold in summer, they wouldn't leave Manchester United crying. At lot of them look like they don't enjoy their football.''