Arsenal manager Mikel Arteta and Chelsea winger, Callum Hudson-Odoi have both tested positive for coronavirus.
The Gunners have closed their training ground and club staff who had recent contact with Arteta will now self-isolate.
The club expects it to be a “significant number of people”, including first-team staff and coaches.
In a statement, Arsenal managing director Vinai Venkatesham said Spaniard Arteta, 37, was “disappointed but in good spirits”.
“The health of our people and the wider public is our priority and that is where our focus is,” he added.
“We are in active dialogue with all the relevant people to manage this situation appropriately, and we look forward to getting back to training and playing as soon as medical advice allows.”
Arsenal are due to play at Brighton in the Premier League on Saturday (15:00 GMT).
On the part of the Chelsea, the club released a statement early on Friday morning to confirm that the winger had tested positive for COVID-19 but that he was doing ‘well’ despite the diagnosis.
All those that came into contact with Hudson-Odoi, including Frank Lampard’s first team squad, have been placed in quarantine and it’s inevitable that this weekend’s match against Aston Villa will be postponed.
Earlier on Thursday, the Premier League said games “will go ahead as scheduled” despite the coronavirus outbreak. But the rate at which many have been infected, the EPL might be suspended to avoid further spread.
Manchester City defender Benjamin Mendy is self-isolating as a precaution after a member of his family was admitted to hospital displaying symptoms of coronavirus.
Three Leicester City first-team players have also self-isolated after showing symptoms of coronavirus.
