All Manchester City players and first-team staff are being tested for Covid-19 again on Thursday, despite recording no fresh cases in Wednesday’s results which enabled the club to reopen the training ground.
Results from the next round of tests will be returned on Friday.
The first-team group will then be tested again on Saturday, the day before the scheduled Premier League match against Chelsea.
The club reported "a number of positive cases" on Monday which led to the Premier League postponing the match against Everton.
Any players that have tested positive are currently in a 10-day self-isolation period and will remain unavailable this weekend.
City have only confirmed two of the players affected, Kyle Walker and Gabriel Jesus, who returned positive tests on December 23 so missed the Boxing Day win over Newcastle.
Those two players can return to the first-team bubble on Sunday, provided they each return a negative test.
While that would be too late for them to re-join the squad to face Chelsea, they could return to training at the start of next week.
That potentially means they would be available to be involved against Manchester United in the Carabao Cup semi-final on Wednesday.
On Tuesday, the Premier League confirmed 18 positive coronavirus tests among players and staff in its latest round of testing (December 21-27) - the highest figure of the season so far.
The Premier League is not considering a potential circuit break at this time.
What is the criteria for a postponement?
The Premier League Board ultimately decides whether matches can or can't be postponed. While there aren't hard and fast rules - each game is judged on a case-by-case basis - there are some guidelines.
For instance, in the 2020/21 Premier League handbook, clubs have been told "permission will not be granted to postpone a league match where the applicant club has 14 or more players listed on its squad list available."
Teams were permitted earlier this season to name 25 players in their Premier League squad list - and that doesn't include registered U21 players.
Man City, for example, according to the Premier League website, named 20 players in their Premier League squad list. They currently have Ilkay Gundogan and Eric Garcia injured, with Walker and Jesus positive with coronavirus. That takes their Premier League squad list down to 16 - but doesn't account for any subsequent positive cases they may have found out about on Monday.
However, City may not even have had to drop below that 14-player level for their match with Everton to be postponed. The Premier League Board have said they took medical advice into consideration when deciding to call off that fixture, and there may have been other factors affecting their decision.
However, what we do know is that the Premier League Board only rearrange games in "exceptional circumstances".