Everton's full first-team squad is in self-isolation after a first-team player reported symptoms of coronavirus.
Everton are due to host Liverpool in the Mersey derby on Monday night, but the game is now in jeopardy.
"The club is in regular contact with the player in question and is monitoring the wellbeing of all players and staff,' said an Everton statement.
"The health, welfare and safety of all Everton players, staff and stakeholders is the Club’s absolute priority.
"Therefore, the club has taken the decision to close down all Everton workplaces including USM Finch Farm, Goodison Park and its headquarters at the Royal Liver Building in Liverpool City Centre. The Club’s retail store at Goodison Park will also close but its Liverpool ONE store is unaffected and will remain open.
"Everton will continue to adhere to UK Government and Public Health guidelines with regards to the closure of its facilities and wellbeing of staff and will be discussing next steps with regards to upcoming fixtures with the Premier League on Friday.
"Further updates will be provided in due course, including guidance relating to forthcoming fixtures."