The Blues face London rivals Arsenal at Stamford Bridge in their first Premier League game back following October's international break.
Mauricio Pochettino is already dealing with the absence of Ben Chilwell, Christopher Nkunku, Romeo Lavia, Wesley Fofana and Marcus Bettinelli, who all remain out.
Now, though, the international break has seen Reece James, Trevoh Chalobah and Carney Chukwuemeka join them on the sidelines.
Captain James is now a major doubt for the clash against the Gunners after suffering a new setback, with the defender being withdrawn from group sessions and now training alone.
Pochettino had been hoping James would be back to full-intensity training following his time out with a hamstring injury suffered in the opening game against Liverpool in August.
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James is optimistic he's avoided another major setback, but he is doubt for the weekend.
Meanwhile, Chukwuemeka was on the bench in the 4-1 win over Burnley following his knee injury he picked up in August.
However, the 19-year-old is now suffering knee pain again and there are fears of a recurrence of a previous injury, meaning he is still working back towards full fitness.
In a statement on Wednesday, Chelsea confirmed both Chukwuemeka and defender Chalobah have both suffered setbacks in their returns.
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"The duo will now go under further review before continuing their rehabilitation at Cobham with the club's medical staff," Chelsea wrote.
Chalobah sustained a thigh injury in August and has missed 10 games so far.
There is also concern over Axel Disasi who has a quadriceps issue.
Cole Palmer missed the England Under-21's game against Ukraine after picking up a knock in the first half of the 9-1 victory over Serbia.
However, it was revealed he suffered a dead leg and he returned to Cobham to recover.
Nicolas Jackson also underwent an operation on his wrist but he isn't expected to be ruled out of the Arsenal clash.
Meanwhile, Armando Broja was also withdrawn from international duty with Albania. That's despite coming back from a nine-month spell on the sidelines with a knee injury to play three games for Chelsea before the break.
Chelsea currently sit 11th in the Premier League after winning their last two games.