Saturday's League Two game between Southend United and Cambridge United has been postponed because of positive coronavirus tests.
The Shrimpers said a "small number" of players have Covid-19.
However, they claim to only have 10 fit outfield players and two goalkeepers available to play, so say they are unable to fulfil the fixture.
Cambridge say they received an email from Southend at 21:40 GMT on Friday requesting the match be called off.
"The club is following all of Public Health England and the English Football League's Covid-19 protocols," said a statement on the Southend website.
Cambridge say further details for the game will be confirmed in due course, but feel the match at Roots Hall should have gone ahead.
"Cambridge United have made representation to both the English Football League and Southend to express our disappointment and that we feel it would still be possible for the fixture to be played," a club statement said.
An EFL statement said: "The circumstances will now be the subject of investigation in accordance with EFL Regulations."