Celtic defender Christopher Jullien will be out for 'three or four months' with a knee injury, Neil Lennon has told Sky Sports.
The 27-year-old collided with the post during Celtic's 3-0 Scottish Premiership win over Dundee United on Wednesday - forced off on a stretcher in the second half - and was subsequently absent from Saturday's defeat to title rivals Rangers.
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"He's a very important player for us," Lennon said before the Old Firm match, which Rangers won 1-0 to go 19 points clear. "It's a bad injury, we will lose him for three or four months. On the eve of this game, it's a hammer blow."
Jullien, who has impressed for Celtic since joining in June 2019 from French side Toulouse, has already missed three months of the season due to a back injury.
Jullien offers support to Lennon
Celtic boss Lennon has come under fire for large parts of the season, and following the Hoops' early Europa League exit at the end of November, Frenchman Jullien spoke out in defence of his manager.
"I have no worries about the trainer because after the game we still believe in each other, we still believe in staff, we still believe in the coach," he said.
"He has our 100 per cent belief in him. He is just a great coach and since I arrived he has done unbelievable work, he was doing it before and he's going to do it again.
"I don't have doubts. We have just to look to each other.
"The staff and the job that the coach is doing is really great. The training that they do for us is just really great.
"I repeat myself but I really think that we just have to believe in each other to get back in the shape that we were in."
Saturday's defeat to Rangers means Celtic now trail their Glasgow rivals by 19 points at the top of the Scottish Premiership, although Lennon's side do have three games in hand.