Chelsea's Romelu Lukaku, Timo Werner, Callum Hudson-Odoi, and the injured Ben Chilwell have tested positive for COVID-19 while Kai Havertz is unwell, manager Thomas Tuchel said ahead of their Premier League home match against Everton later on Thursday.
"Kai feels unwell, he's not positive yet but we're waiting for test results and we decided to not bring him to the squad," Tuchel said.
"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... The situation started yesterday with the players feeling unwell and not training."
On top of the new cases, Chelsea midfielder Mateo Kovacic recently recovered from injury only to have to isolate after testing positive for COVID-19.
"We still have a strong squad and one we want to push forward, and that should be able to compete," Tuchel said before the kickoff against Everton. "Like always, we focus on the guys who are there."