Charlie Nicholas says the arrival of Alexis Sanchez has spoiled Manchester United's system and he must be dropped following their Champions League exit.
Jose Mourinho's side lost 2-1 at home to Sevilla on Tuesday evening to exit the Champions League at the last-16 stage, meaning the FA Cup is now their only realistic chance of a trophy this season.
Sanchez joined from Arsenal in January, but gave the ball away on 20 occasions in the game, and Soccer Special pundit Nicholas believes his arrival has had a negative impact on Mourinho's formation.
He said: "At the start of the season, Manchester United had a fluency to them. Paul Pogba played high up with Jesse Lingard behind him and Romelu Lukaku on his game.
"All of a sudden Sanchez comes, Marcus Rashford gets dropped out and Anthony Martial gets moved over. All of a sudden the whole team is getting squeezed to fit Sanchez in.
"Sanchez, at the moment, does not deserve to be in the team. It's too individual. He is giving the ball away too often.
"I'm sure a lot of Manchester United fans must be looking and saying 'when is he going to do something for us?'
"He looks as though he is trying hard, but this is Manchester United and you've got to deliver on a game-by-game basis and he is not."
Rashford scored twice against Liverpool in a 2-1 win at the weekend, but was moved over to the right against Sevilla and Nicholas feels that was a mistake.
He added: "Rashford started on the right when his success at the weekend was on the left and that was to accommodate Sanchez.
"I just don't think this works.
"Mourinho is a genius - and has been - at getting individual players and saying 'this is the system, this is how it's going to operate.'
"It just doesn't seem that it's functional. There's no fluency and there's no rhythm to the team.
"Because of that, individuals are trying to look after themselves - and that puts pressure on the back four. They've got the best keeper in [David de Gea] the world and now he looks frustrated because he is getting isolated.
"It felt like a matter of time before Seville would go and score."
United trail Manchester City by 16 points in the Premier League, but face Brighton in the quarter-final of the FA Cup on Saturday.
After winning the EFL Cup and the Europa League last term, there is now a risk Mourinho's second season in charge could end without silverware.
Nicholas added: "They did not justify being anywhere close to the last eight of the Champions League. They are not going to get the title and now have got the FA Cup to play for.
"Jose rescued an average Manchester United last season to get them into the Champions League with two trophies. Now he is staring down the barrel of winning zero."