Sunderland's League One rivals Peterborough have become the latest team to postpone games after a coronavirus outbreak.
Posh's next three fixtures against Ipswich Town this Saturday, December 19, Gillingham on Boxing Day, and Charlton Athletic on Tuesday, December 29 have all been suspended.
The club confirmed that one unnamed player has tested positive for coronavirus and three others are displaying symptoms.
The Club said: "The safety and health of our players is paramount. The club have notified the EFL of the postponements.
"The next scheduled league fixture is on January 2, 2021 against Doncaster Rovers at the Weston Homes Stadium. The club will be making no further comment."
An EFL spokesperson said: "The club informed the EFL that they would be unable to fulfil the fixtures following a recent positive Covid-19 test and the the requirement for players and staff to self-isolate for 10 days as per EFL and Government guidance in order to mitigate against the risk of further infection.
"The circumstances surrounding the postponements will now be subject of an investigation in accordance with EFL regulations.
"Revised dates for the rearranged fixtures will be confirmed in due course."
Sunderland's players are currently isolating following a Covid-19 outbreak at their training ground.
The Black Cats next scheduled game is on December 29 against Accrington Stanley.
