The EFL will now open an investigation into the circumstances surrounding the cancelation of the game, as it does with all such postponements.

A statement on Rotherham’s official website read: “Following a number of further positive cases of Covid-19 confirmed last night within the Rotherham United first-team squad, we have reluctantly – but with the safety of our players and staff at the forefront of our minds – informed the EFL and our opponents, Middlesbrough, that we will be unable to fulfil our Boxing Day fixture.

“Paul Warne’s side were set to face Boro at The Riverside on Saturday 26th December 2020, but following an increased series of testing throughout the early stages of this week, brought about by the postponement of last weekend’s fixture against Derby County, the club have, following consultation with the EFL doctors, been left with no choice but to inform the EFL of our decision to rearrange the game against Middlesbrough.

“The club will continue to monitor the severity at which the virus has spread – alongside the health and well-being of our first-team squad and those connected to them – whilst remaining in contact with our upcoming opponents and the EFL on the matter.

“We hope to make a decision on future fixtures later today as we continue discussions with the EFL, with whom we will work closely, to ensure the safety of everyone connected with the football club at the forefront of our minds.”

The EFL will now look into the matter, with rearranged fixtures set to be confirmed “in due course”.

A statement from the EFL read: “Rotherham United’s Sky Bet Championship fixture against Middlesbrough on Saturday 26 December has been suspended.

“The club informed the EFL that they would be unable to fulfil the fixture following recent positive COVID-19 tests and the requirement for players and staff to self-isolate as per EFL and Government guidance in order to mitigate against the risk of further infection.

“The circumstances surrounding the postponements will now be the subject of an investigation in accordance with EFL Regulations.

“Revised dates for the rearranged fixtures will be confirmed in due course.”

Meanwhile, the Football Association has announced that out of 864 coronavirus tests carried out across the Women’s Super League and Women’s Championship from December 14 to 20, 32 have returned positive.

Elsewhere, Portsmouth’s next two Sky Bet League One fixtures have been postponed by the EFL following five confirmed cases of Covid-19.

League leaders Pompey were due to host Swindon on Boxing Day before a trip Bristol Rovers on December 29.

The south-coast club announced that the positive tests affect both playing and backroom staff, including defender Jack Whatmough, who missed Friday’s win at Hull after feeling unwell.

“We wish all those who have been affected by this terrible virus a speedy recovery and our best wishes go out to them,” read a Portsmouth statement.