Christian Pulisic was among four Chelsea players that started to isolate after four players tested positive for coronavirus on Thursday. The USMNT star was joined by Mason Mount, Tammy Abraham, and Fikayo Tomori in isolation, though it's unknown if the four players contracted the virus, according to Goal.

The Blues first-team squad underwent coronavirus testing at the end of last week upon their return to training, something all Premier League teams have been asked to do ahead of the impending new season, which is set to begin the weekend of Sept. 12.

The four aforementioned youngsters could be merely following government guidelines if they traveled from abroad, as the United Kingdom is currently enforcing 14-day self-isolation for people come from a country listed as high-risk in terms of infection rates.

Eight squad members now quarantining, which has thrown a wrench in Frank Lampard's plans, especially with a likely starter like Christian Pulisic on the mend.

Other Premier League sides like Sheffield United, West Ham, Brighton, and most recently Manchester United with Paul Pogba testing positive hours ago — have all recorded positive coronavirus cases in their squads.  There have been 14 positive cases confirmed across 12 Premier League clubs.

The Blues will be part of a pilot scheme in which the Premier League will introduce fans back into stadiums. Chelsea will travel to Brighton for a friendly on Saturday, as the Seagulls' Amex Stadium is slated to hold 2,500 socially-distanced spectators.