The Mail report Chelsea have confirmed several players have tested positive for the virus and have been ordered to stay at home to reduce the risk of infecting teammates and colleagues.
Among those in isolation are Mason Mount, Tammy Abraham, Christian Pulisic and Fikayo Tomori – all of whom have just returned from holidaying in Mykonos, Greece, though it is not known whether any have contracted Covid-19.
Frank Lampard has already begun preparations for the new season at Chelsea’s training HQ in Cobham but will have to wait to be joined by those in quarantine.
Each player currently in isolation has undergone a test to determine whether they are carrying the virus ahead of their return to training.
In the cases of Abraham and Mount it could even scupper England’s plans as both players are due to report for Three Lions training on Monday ahead of next month’s Nations League fixtures after being included in Gareth Southgate’s squad.