Saturday's League One match between Oxford United and Swindon has been suspended after a number of positive coronavirus cases at the Wiltshire club.
The two teams were due to meet at the Kassam Stadium but the match has now been postponed until a later date.
A statement from the EFL and both clubs said: "The decision has been taken following a request from Swindon Town following the identification of a number of positive COVID-19 cases at the club and due to concerns raised over the potential risk of further infections.
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"The circumstances surrounding the postponement will be the subject of an investigation in accordance with EFL Regulations.
"A revised date for the rearranged fixture will be confirmed in due course."
The derby is the second League One match on Saturday to be postponed due to the virus.
On Thursday Accrington Stanley's home game against Bristol Rovers was called off after eight Stanley players tested positive for coronavirus.
Accrington said all eight players were now self-isolating while two members of staff have also been affected.
In a statement Accrington said: "Due to the number of positive cases of COVID-19 within the Accrington Stanley squad and the requirement for players and staff to subsequently self-isolate as per EFL and Government guidance, the club has advised the EFL it is unable to safely fulfil this weekend's fixture.
"Eight Stanley players have tested positive and are self-isolating, a member of staff has tested positive while another member of staff is already self-isolating."
The circumstances of the postponement of Accrington's match will also be investigated by the EFL.