Antonio Conte has insisted that Chelsea's medical team are trying to get to the bottom of David Luiz's ongoing knee injury.
The centre-half has been absent from the Blues' starting lineup in recent weeks - initially after a spat with Conte and then through injury.
Speaking to the press (as quoted by football.london) about when fans could expect to see Luiz available again, Conte explained that it could be a while as his medical department tried to find a solution to the inflammation on the Brazil international's knee.
He said: "David has a big inflammation on his knee, we are trying to solve this situation with the doctor. He is being assessed day by day. I don’t know when he will be back with us."
The 30-year-old defender has not played a single minute of the club's last eight matches in all competitions due to the complication, and it may be well into the New Year before Luiz is available for selection again.
The 47-year-old also revealed that Michy Batshuayi would be available to play some part in Saturday's match against Southampton after he overcame an ankle injury that kept him "out for three weeks".
David Luiz should probably train himself to be a CM permanently. He's an absolute monster when he plays there and I gotta say that Christensen is far better choice at CB alongside Rudiger and Azpi— 🎧 (@HakunahMorata) December 15, 2017
Meanwhile, Conte has also addressed his plans for the upcoming January transfer window as he looks to bolster his tired first-team squad.
The Italian has spoken often about wanting to recruit new players to his cause when the window opens again on January 1 and, while he stated that work was ongoing on that front, Conte admitted that the final decision over bringing new players in would be down to the club.
He said: "I think that it’s right to have a meeting with the club about the transfer market in January. I stay here to work, for the transfer market you have to ask the club. I can give my opinion, but the last decision is with the club."