Chelsea announced on Thursday the covid positives of Romelu Lukaku, Timo Werner, Callum Hudson-Odoi and Ben Chilwell.
The players have been left out of the squad against Everton, although Chilwell was injured, and will now have to undergo 10-day isolation.
Kai Havertz is ill too, but has not tested positive. As Thomas Tuchel explained in the preview of the game against Everton, the squad underwent additional tests on Thursday morning, after several players were unwell before training on Wednesday.
This announcement comes after five of the ten matches of the day this weekend have been suspended due to the high number of cases between various teams in the Premier League.