Nottingham Forest have been forced to cancel Saturday's pre-season game against Burnley at the City Ground because of Covid-19 cases at the club.
It is the second friendly called off by Forest following Wednesday's away match against Aston Villa.
Forest say a "small number of players" returned positive tests and are now self-isolating.
A statement said the club would "rigorously adhere" to the guidelines to protect players and staff.
The Covid cases were identified as part of Forest's on-going testing programme.
Forest kick off their new season with a trip to Coventry on Sunday, 8 August, followed by home games against Bradford City and Bournemouth in the EFL Cup and Championship.
"It is disappointing that we have not been able to get a run-out against Premier League opposition but Sean Dyche and Burnley Football Club have been very understanding for which I am grateful," said boss Chris Hughton.
"I am also very disappointed that Forest supporters will have to wait a little bit longer to return to The City Ground but the team and I look forward to welcoming them back against Bradford and Bournemouth.
"The focus of everybody at the club is now to prepare for the Coventry fixture."