Manchester - Jose Mourinho admitted he is not certain if Manchester United defender Eric Bailly will play again this season after revealing he may need surgery on a persistent ankle injury.
Bailly, 23, has not played for United since a defeat at Chelsea at the start of last month, having sustained the injury while on international duty with the Ivory Coast.
And United manager Mourinho, who signed the centre-back from Villarreal last year, admits he is concerned by the lack of progress.
Speaking after Wednesday's 1-0 victory over Bournemouth, Mourinho said: "I think it's serious. I don't know. It's an injury that comes from last time he went to the national team.
"Since then we were trying a conservative treatment but if that conservative treatment is not resulting how we want, he will either have surgery or a procedure. Let's wait a little bit more.
"I'm not a doctor, probably the doctor can inform you, there is nothing to hide. I don't want to be pessimistic."
In Bailly's absence, England pair Chris Smalling and Phil Jones have established themselves as Mourinho's centre-back pairing of choice until Marcos Rojo returned from a long-term injury lay-off of his own recently.
"Tonight, we had Smalling and Jones," said Mourinho. "Lindelof was on the bench, Blind was on the bench, Marcos Rojo was injured, but nothing serious.
"During the whole season we had problems with central defenders but because we now have four or five (of them) we always manage. And Chris Smalling is playing amazingly well now, for seven or eight matches in a row. So we are fine."
One player who was not involved in the victory over Bournemouth was midfielder Henrikh Mkhitaryan, who has started just one league game since the end of October, and has been left out of the squad entirely in recent games.
"I can only have six players on the bench," said Mourinho. "And I try to have some balance on the bench."
United won the game to start their recovery from the damaging weekend defeat by league leaders City in the Manchester derby.
And, although his team remain 11 points behind Pep Guardiola's in-form league leaders, Mourinho refused to concede the title race is over.
Mourinho said: "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."
Mourinho also praised the attitude of his players and the manner in which they responded to losing their 40-game unbeaten run at Old Trafford against City on Sunday.
"I think we showed a very good attitude, a very good determination to win," he said.
"I think every time, after a defeat, you try not to have a second defeat and that was in the back of their minds when they were playing.
"They wanted to win the match, I could see that from the first minute until the last second."
United needed a first-half goal from Romelu Lukaku against the run of play to defeat Bournemouth although Cherries manager Eddie Howe thought the Belgian, who was cautioned later for a foul on Harry Arter, should have been booked before his goal for a foul on Nathan Ake.
"Yes, I did," he said. "I had a chat with the fourth official, I thought he was late on Nathan, then he picked up another one. He should have been off the pitch.
"The referee missed a couple, that was difficult. I just had a quick chat with him afterwards."