Sunderland have informed the English Football League they will not be able to fulfil their next three matches after the club's Covid-19 outbreak.
The trip to Shrewsbury Town (19 December) and home matches with Blackpool (22 December) and Hull City (26 December) have all been postponed.
Eight players missed Tuesday's League One 1-1 home draw with Wimbledon.
Sunderland made the decision to go ahead with that game but the club were "unclear" on potential EFL sanctions.
After one senior player tested positive for coronavirus on Monday, a further four cases have now been confirmed among players and staff at the club's Academy of Light training base.
Sunderland have earmarked Sunday, 27 December as a date to return to training before their game at Accrington Stanley on Tuesday, 29 December.
"It is with a heavy heart that I have informed the EFL that we are unable to play our next three league fixtures," said Sunderland chief executive James Rodwell. "The welfare of our players, staff and opponents remains the number one priority."
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