Southend's match at home to Cambridge has been postponed after positive coronavirus cases in the Shrimpers squad.
The Sky Bet League Two club say they would not be able to field a team for Saturday's fixture.
A club statement read: "This is following a small number of players testing positive for Covid-19, the EFL's doctor instructing another squad member to isolate due to their close proximity of a player who tested positive and a plethora of players being unavailable due to injury.
"The club would only be able to field a maximum of 10 professional outfield players and two goalkeepers in the matchday squad and because of this the club have advised the EFL that it is unable to safely fulfil the fixture."
However, Cambridge are unhappy at the postponement.
"Having received an email from Southend United Football Club at 9:40pm this evening, stating their wish for the game to be postponed, Cambridge United have made representation to both the EFL and Southend to express our disappointment and that we feel it would still be possible for the fixture to be played."