Saturday's Championship fixture between QPR and Wycombe Wanderers has been postponed after the visitors reported positive Covid-19 tests.
The club informed the English Football League it would be unable to fulfil the fixture following the latest tests.
Wycombe have not stated how many positive results were recorded or how many players or staff are affected.
The circumstances surrounding the postponement will now be subject to an EFL investigation.
A new date for the fixture at QPR's Kiyan Prince Foundation Stadium has yet to be confirmed.
Wycombe, whose next match on Tuesday against Sheffield Wednesday was already postponed, are bottom of the table and four points adrift of safety, while QPR are 18th.
It is the third of Saturday's scheduled Championship fixtures to be postponed after Brentford's trip to Reading and Sheffield Wednesday's match at Coventry were also called off due to coronavirus cases at the Bees and the Owls.
Shrewsbury Town against Lincoln City in League One and Mansfield Town against Carlisle United in League Two have also been postponed.
Carlisle's next three fixtures are off after positive cases forced the club to close their training ground.