Kai Havertz returned a positive test for COVID-19 and missed the Champions League clash against Rennes.
The 21-year-old midfielder will now observe a period of self-isolation.
Chelsea made the announcement via their Twitter account saying: “Frank Lampard has confirmed Kai Havertz has tested positive for Covid-19.
“As a consequence the player is now undergoing a period of self-isolation and is not involved in tonight’s Champions League game versus Rennes.”
Fans may now be wondering how many games the attacking midfielder will miss.
According to the NHS guidelines, anyone who tests positive for coronavirus must self-isolate for at least 10 days.
The German international will now miss Chelsea's home fixture against Sheffield United on Saturday.
Football then goes into another international break, meaning the Chelsea star could return for the Blues' trip to Newcastle on November 21.
Havertz, who signed a five-year deal with the club, has scored four goals and provided three assists in 10 appearances across all competitions.
This article was most recently revised and updated 2 years ago