Boss Antonio Conte said the centre-back, who has found himself on the fringes of Chelsea's starting XI, is among several injury concerns, with Charly Musonda definitely out and Michy Batshuayi and Kenedy not yet at 100 per cent.
And it appears as though David Luiz may be set for a spell on the sidelines as Chelsea attempt to determine the full extent of his troublesome knee.
"I must be honest at the moment it is difficult for me to answer [how long he will be out]," Conte told a news conference ahead of Wednesday's away fixture.
"It will be up to the doctor to assess it and take the best decision. I don't know [how long]."
There was better news on wing-back Victor Moses, though, who is back in contention for the first time since damaging his hamstring last month.
"He is in contention but at the same time I have to make the best decision for every player," he added.
"For sure Victor is back from a bad injury and needs a bit of time to find the best physical condition. He is an important player for us."
Conte reports David Luiz (knee problem) and Charly Musonda are out, and Michy Batshuayi and Kenedy are trying 'to come back to 100 per cent'.— Chelsea FC (@ChelseaFC) November 28, 2017
Conte has made no secret this season of the fact he believes Chelsea to be lacking in depth, and the Italian conceded that more injuries would leave his squad stretched.
"Yeah [injuries will stretch the squad], but my hope, my hope, first of all is to have all my players available," he said.
"I have spoken before about our problems at the start of the season. We started with a lot of problems because we started the season with a lot of injuries – with [Eden] Hazard, then Pedro in pre-season, then N'Golo [Kante] and Moses.
"For sure, it's always important for every team to have all the players available. We know our situation and we try to do our best in every moment.
"Then, I repeat, I'm very happy to work with my players and try to face every situation: easy or difficult situations."