MANCHESTER -- Manchester United have confirmed that the injury that has already ruled Eric Bailly out of their last eight games may require surgery, with Jose Mourinho calling the Ivory Coast international's setback "serious" after a 1-0 win against Bournemouth.
Bailly, 23, has not played since the 1-0 defeat at Chelsea on Nov. 5 after returning from the October international break with a groin injury.
Bailly missed four games before recovering to start three consecutive games against Tottenham, Benfica and Chelsea before meeting up with Ivory Coast again in November.
He did not play in the 2-0 defeat to Morocco because of suspension and returned to the club with an ankle injury and has not played for United since.
Mourinho said the club's medical staff are considering surgery to correct the problem but will wait to see how the centre-back responds to "conservative treatment."
Mourinho said: "I think it's serious. It's an injury that comes from the last time he went with the national team.
"We are trying a conservative treatment but if the conservative treatment is not working, probably he will have a surgery procedure but let's wait.
Probably the doctor can inform, is not a problem for me, it is nothing to hide, I just don't want to speak about it."
Mourinho was also without Marcos Rojo for the Bournemouth match at Old Trafford on Wednesday night, choosing to pair Phil Jones and Chris Smalling at centre-back.
The United manager was asked directly whether Bailly's season could be over, but he insisted he did not want to be "pessimistic."
He added: "I want to leave it with the doctor. But today, we play with Smalling and Jones, Lindelof on the bench, Marcos Rojo is injured but nothing really big so during all season we have problems with central defenders. Chris Smalling is playing amazingly well, so we are fine."
Mourinho also chose to omit Henrikh Mkhitaryan from his squad for the seventh time in eight games.
However, he insisted Mkhitaryan's only problem was being part of a big squad.
He added: "I can only have six [outfield] players on the bench and I try to have some balance on the bench.
"I had two defenders that can play in different areas, I have Ashley Young to cover the wing and wing-back positions, Herrera is a midfield player, Zlatan is a striker, Rashford is a second striker and a winger.
"To have Mkhi means I don't have one of them and I believe the others deserve."
United remain 11 points behind Manchester City in the title race after Pep Guardiola's side won 4-0 at Swansea. But with 21 games still to go, Mourinho insists his team have not given up of catching their rivals.
He told the BBC: "I said we play match after match and the next we have to try to win, we have a difficult one at West Brom and we try match after match.
"It is only over in May, if it is over now I go on holiday to Brazil or Los Angeles."