Chelsea's Ben Chilwell, Callum Hudson-Odoi, Timo Werner and Romelu Lukaku have all tested positive for coronavirus and therefore been ruled out of Thursday's game with Everton.
The match against the Toffees was believed to be in doubt on Thursday afternoon when Chelsea returned more positive coronavirus tests, adding to Mateo Kovacic, who is currently self-isolating.
Thursday's fixture is going ahead, but Chilwell, Hudson-Odoi, Werner and Lukaku were all notable absentees when the squad was revealed ahead of kickoff.
Blues head coach Thomas Tuchel has confirmed that the four first-team players have all tested positive for the virus, which is currently causing chaos in the Premier League.
Tuchel added: "Kai [Havertz] feels unwell, he's not positive yet but we're waiting for test results so we decided not to bring him to the squad.
"We did some extra tests at 12 o'clock today to make sure who would arrive at lunch. From there we had to pick the team. Would it be the same lineup? I don't know. The situation started yesterday with the players feeling unwell and not training.
"We had to confirm the flow tests and wait for the PCR results. The results are the results and the situation is the situation. We still have a strong squad and one we want to push forward, and that should be able to compete. Like always, we focus on the guys who are there."
Five of this weekend's Premier League matches have already been postponed due to COVID-19 outbreaks in a number of squads.
