Jose Mourinho has suffered a double injury set-back with Eric Bailly requiring ankle surgery that will rule the defender out for up to three months and Marouane Fellaini sidelined until next month with a knee injury that has already kept the midfielder out for three weeks.

Bailly has missed United’s past eight matches and Mourinho revealed the decision had now been taken for the Ivory Coast centre-back to undergo an operation on his ankle, although he is confident the defender will play again this season.

“Eric is going for surgery – the decision is made. I don’t say [he’s out] for the season but it it’s for the next two or three months,” said the United manager, who is also without defender Marcos Rojo (head) for Sunday’s trip to West Bromwich Albion.

“But now we have [Phil] Jones back and we have [Chris] Smalling, even [Daley] Blind, so it’s a position we have good cover in but of course we’ll miss the player.”

Bailly's ankle surgery will keep him out for two to three months credit: Action Images via Reuters

Fellaini has missed United’s past five matches after aggravating a knee problem originally sustained on international duty with Belgium in early October and the club have decided the midfielder requires a longer period of rehabilitation in order to make a full recovery.

The 30-year-old suffered third degree medial collateral ligament damage that forced his substitution for Belgium against Bosnia-Herzegovina on Oct. 7 but he suffered complications upon his return against Chelsea a month later.

He played through the pain barrier to feature against Newcastle, Basel and Brighton but the situation has only worsened and he will now miss the entire festive programme in a blow to Mourinho.