Norwich City's game against West Ham United on Saturday has been postponed due to an outbreak of Covid-19 in the city camp.
The Canaries confirmed the news in a statement released on Thursday evening, and said the decision had been made "following PCR test confirmation of positive COVID-19 results, injuries and illnesses within City’s playing squad and staff."
The club also confirmed that the affected players are now self-isolating, and apologised for any inconvenience caused to West Ham United and both sets of supporters.
City had recently faced both Manchester United and Tottenham, who have had to postpone recent matches due to Covid.
Winger Christos Tzolis is the only confirmed positive case at the club so far, but head coach Dean Smith confirmed after Tuesday's defeat to Aston Villa that more players have reported feeling unwell.
Josh Sargent, Lukas Rupp and Pierre Lees-Melou all dropped out of the squad at late notice ahead of the clash against Villa, but it is not known yet whether their absences were down to illness or injury.
Norwich players were tested again at the Lotus Training Ground on Thursday and the outcome of those results will now help the club determine the scale of the outbreak they are facing.
The Canaries' sporting director Stuart Webber approached the Premier League ahead of Tuesday's match against Villa to seek guidance, with the club currently without 10 first team players due to a combination of illness and injury.
Pressure is building on the Premier League to postpone the upcoming set of fixtures to give clubs time to control the spread, with Brentford boss Thomas Frank suggesting a short circuit-breaker in his press conference on Thursday.
"Everyone is dealing with it and everyone has a problem at this moment in time," Frank said.
"To postpone this round [of Premier League games] and the Carabao Cup would give everyone a week at least to clean and do everything at the training ground so everything is fine and we break the chain at every club."
Football League impacted as well
While Norwich's match against Aston Villa survived on Tuesday, a number of other Premier Leagues matches have been called off, including Watford's trip to Burnley on Wednesday and Leicester City's match against Tottenham Hotspur on Thursday.
Saturday's fixture between Manchester United and Brighton and Hove Albion has been postponed too, but the Premier League has insisted that it intends to "continue its current fixture schedule where safely possible".
Matches further down the footballing pyramid have been affected as well, with Northampton Town's home game against Barrow in League Two becoming the latest fixture to be cancelled on Thursday.
In a statement, the Cobblers said they informed the EFL that they would not be able to fulfill the fixture following a number of positive cases among their first team squad.
The club are also expected to make an announcement about their Boxing Day fixture against Walsall "in due course".
In a message to fans, the Cobblers said: "Supporters are asked to keep their tickets safe as tickets and packages purchased for the game will be valid for the rearranged date.
"Details of refund options for match ticket holders unable to make the rearranged date will be confirmed when the new date is known."
The announcement comes just a day after Luton Town's Championship fixture at Reading was also called off.
The two clubs were due to meet at the Select Car Leasing Stadium on Saturday, but Reading said an outbreak meant they would be unable to field a team.
In a statement, a Reading club spokesperson said: "The club informed the EFL [on Wednesday] that, following the return of a significant number of positive PCR tests within our first team and Under-23 squads, we are unable to field a team capable of fulfilling the fixture on Saturday."
The EFL said it would now look at the circumstances surrounding the postponement and work with affected clubs to assist them.
A rearranged date for the fixture has yet to be confirmed.
Reading added: "We apologise unreservedly for the inconvenience and disappointment this causes to both home and away supporters, who were understandably looking forward to attending this fixture.
"However, the health, safety and welfare of our players, coaching team and club staff remains of paramount importance and our primary concern now is to ensure the swift and full recovery of those affected."
Luton said fans would have their tickets refunded and wished all the players and staff at Reading a full and speedy recovery.
Covid passes to become part of matchday experience
In a bid to protect fans, the government has insisted that supporters must now show their NHS Covid passes to be able to get into matches with crowds of more than 10,000.
A negative lateral flow test taken within 48 hours of the event will also be accepted.
A crowd of more than 28,000 are expected at Portman Road for Ipswich Town's big League One match against Sunderland on Saturday and the club are confident they will not face any problems getting fans into the stadium.
However, they are encouraging supporters to arrive earlier than normal to avoid any potential delays.
Mandatory Covid passes are not required for clubs where the capacity is lower than 10,000 but League One side Cambridge United have made the decision to carry out random checks due to high infection rates in the area.