Middlesbrough and Sheffield Wednesday’s preparations for Saturday’s FA Cup third-round ties have been affected by positive Covid-19 cases within first-team players and staff.
Boro are scheduled to visit Championship rivals Brentford, while the Owls are away at League Two side Exeter City.
Both clubs have had to close their training grounds.
Derby confirmed a similar outbreak before their FA Cup tie at Chorley.
The Rams have isolated their entire first-team squad and first-team coaches, including interim boss Wayne Rooney, for the game and will instead field a side comprising of under-23 and under-18 players.
Boro boss Neil Warnock could be forced to follow suit, with the under-23 squad within the testing programme as part of the club’s preparations for the cup fixture.
Wednesday have not confirmed if any of their playing staff are among those to have tested positive but have revealed that caretaker boss Neil Thompson and his temporary assistants Lee Bullen and Steven Haslam are isolating, so the team they field at Exeter will be led by academy coach Andy Holdsworth.