Manchester United have been dealt yet another injury setback after Mason Mount suffered a calf strain that could keep him out of action for up to a month.

Mount was hurt in training ahead of United’s trip to Everton on Sunday. The club’s medical staff are still assessing the problem, but the early indications are that he could be out for between three and four weeks.

It’s another huge setback for Mount who has struggled to make an impact since joining United from Chelsea for £60million in the summer, and has already missed six games through injury this season.

The 24-year-old joins other central midfielders Casemiro and Christian Eriksen on the sidelines as United continue to be dogged by injury problems at a crucial stage of the season.

It comes as Luke Shaw prepares to play for the first time in three months at Goodison Park after recovering from a torn thigh muscle. The England defender played in the first two games of the season but has not been seen since.

Mason Mount has been handed another injury setback after already missing seven games

Erik ten Hag is facing a central midfield crisis with Casemiro and Christian Eriksen on the sidelines

Left back Luke Shaw could make his return after three months out with a thigh injury on Sunday

Goalkeeper Andre Onana is also available despite flying home early from international duty with Cameroon after suffering a groin strain in the World Cup qualifier against Mauritius.

However, Rasmus Hojlund faces a late fitness test on the hamstring strain he suffered against Luton a fortnight ago.

Hojlund withdrew from Denmark’s games against Slovenia and Northern Ireland, and United boss Erik ten Hag confirmed that his £72m signing faces a race against time to be fit for the Everton game.

‘Rasmus is a close finish,’ said Ten Hag. ‘He’s training, he finished outside. He’s making very good steps and we have to wait until tomorrow and we will make a final decision. Luke Shaw will be available for Sunday, he will be in the squad. Andre is okay, he stepped in training today, he’s good.’

Ten Hag admitted that Shaw’s return will be a major boost after United were forced to use a number of different players at left-back in his absence this season.

‘You can mention many things,’ he added. ‘You can mention his physicality, his technical ability, his leadership, it’s clear. A long time in the season we didn’t have a left-back. We are very happy he’s back, it’s a good sign. He will help us be more stable, I am sure of that.’

However, the United manager confirmed that Jonny Evans is not ready to return from the hamstring strain he suffered in the 4-3 Champions League defeat to FC Copenhagen in Denmark earlier this month.

‘He’s on the way back, but he’s not ready for Everton – it will not take long,’ said Ten Hag.

Rasmus Hojlund will face a late fitness test ahead of Sunday’s clash after an injury against Luton

Andre Onana suffered a groin strain with Cameroon but is thought to be in line to feature

Jonny Evans suffered a hamstring strain in the defeat to Copenhagen and a return against Everton is too soon