Manchester United defenders Jones and Smalling facing lengthy injury absence

United have failed to threaten title favourites Chelsea in the Premier League this term, while Mourinho's side risk missing out on the Champions League places as they now lie fifth.

Jones, 25, picked up a toe injury in an innocuous training ground tackle, with reports claiming it involved Smalling.

Mourinho is also without the suspended Zlatan Ibrahimovic and Ander Herrera as United start April with a league game against West Bromwich Albion on Saturday.

According to Manchester Evening News, Mata trained as normal this week but complained of an issue to his groin on Thursday, with United quickly taking the decision to rectify the problem with an operation.

They can achieve that goal by finishing in the top four of the Premier League or by winning the Europa League, in which they play Belgium's Anderlecht in the quarter-finals.

Mata's blow is the latest concern for United, following quickly on from Mourinho confirming "long-term injuries" to defenders Chris Smalling and Phil Jones.

"If a player wants to move to London, enjoy London - we don't want you, " Mourinho said. "He will want to strengthen his spine but we are seeing defensive midfielders are the most important players in any team". "We know we're playing against a club that are financially miles in front of us but you get games like that in this league and you still can manage to win games if it goes right for you".

'There are handsome places to live.

West Brom boss Tony Pulis: "There's no complacency". "The important ones are the ones that are ready to play".

"They have to be resilient, they have to be professionals, " Mourinho said of his players.

'The players have to understand what the team needs, they have to go to the limits, they have to play with small injuries, they have to play with pain'.

"So we want every match to be important until the end of the season and if we manage that, to be in the run in the two competitions, the boys have to be very resilient, very strong mentally".

  • Julie Sanders