Chelsea have been forced to put N'Golo Kante's return on hold.
Manager Frank Lampard said prior to the midweek Champions League trip to Ajax that Kante's fitness would be assessed ahead of Saturday's teatime clash at Burnley.
The key midfielder has been plagued by fitness problems this season and suffered his latest injury, a groin issue, on international duty with France.
Lampard revealed the club are now taking a "step back" with Kante's recovery, and could not put a timeframe on the 28-year-old's return.
He said: "N'Golo won't be ready. He is outside on his own doing physical work to deal with a few issues.
"We need to get him right now because he has been in and out through the whole season.
"I just want him fit, he has played a lot of football for four years. He had a big injury off the back of last season.
"So I think that maybe he is suffering from that big injury and a little fall-out from that.
"I think now it is time to take a small step back just to get his fitness up and be confident that we won't have a domino effect with small injuries, so there's no actual timeframe."
Antonio Rudiger, Andreas Christensen and Ross Barkley will also miss out at Turf Moor.
England midfielder Barkley turned his ankle against Newcastle last weekend and, although the problem is not serious, he is still unavailable.
It seems Christian Pulisic has not yet earned a start despite his sparkling display in Amsterdam.
The £58million winger has started only three Premier League matches this term, but he came off the bench to set up Michy Batshuayi's winning goal four minutes from the end.
Lampard said: "I think the way he has played he has deserved a starting place regularly in the last few weeks – but so do others.
"It is brilliant that he is coming on and making an impact, of course he will get his starts.
"It's the reason he has come here, but we have Callum Hudson-Odoi who was top class against Newcastle, and Willian who was our best player in four or five games."
Lampard revealed he is keen to tie youngsters Tammy Abraham and Fikayo Tomori to long-term contracts.
Mason Mount agreed a new deal over the summer but his fellow England rookies have yet to follow suit.
"They are doing particularly well but I leave those conversations to the club to discuss contracts but, of course, I want them to be here for a long time," said Lampard.
"That's the conversation for me and the club I suppose. I made it clear that they are playing very well and I want them to stay."
