Sunderland tried to postpone Tuesday night's home game against AFC Wimbledon after a Covid-19 outbreak saw them lose eight players - but they could not reach an agreement with the EFL.
One senior player has tested positive while seven others were deemed 'close contacts', two of which are displaying symptoms.
The EFL told the club they could postpone the fixture, but that it would be subject to an investigation.
Sunderland say they took the decision to play the game due to the 'lack of clarity' as to the sanctions they could face.