Graham Potter has revealed that Mason Mount will remained sidelined until April through injury.
Mount has not featured in any of the Blues' last three fixtures, all of which have been won, due to suspension and fitness issues.
Earlier this week, it was claimed that the playmaker had felt fit enough to play some part of last weekend's 3-1 success at Leicester City.
However, at a time when talk of his long-term future is frequently the topic of conversation, the academy graduate was forced to remain on the sidelines.
When Mount was selected in Gareth Southgate's England squad on Thursday, it was assumed that he would be made available to represent Chelsea versus Everton on Saturday evening.
Instead, Potter told reporters at a press conference on Friday that the 24-year-old would sit out the meeting with the Toffees and England's double-header with Italy and Ukraine due to an issue with his pubic bone.
Potter also revealed at the same media briefing that Raheem Sterling was continuing to recover from a hamstring injury, although he insisted that it was "not too serious".
Thiago Silva was a known absentee due to a knee injury, but Potter acknowledged that Cesar Azpilicueta would remain unavailable a month on from sustaining a head injury versus Southampton.
While the Spaniard has served the mandatory protocol period, he will not come back into contention until the start of next month at the very earliest.
There was positive news regarding the availability of N'Golo Kante, who has not bee involved for Chelsea since suffering a hamstring injury on the second weekend of the season.
Potter stated that the French midfielder "as a chance of being back in the squad", the expectation being that it will only be among the replacements.
Later in the press conference, Potter added: "He's been a huge miss to us. It's great for us he is back and we have to be mindful he has a long injury. We have to take the steps to get him up to speed in the Premier League."
Reece James is expected to return to the squad after being unavailable last weekend due to illness.