Kilmarnock's Premiership match with Motherwell is set to be called off with the home side's entire squad "advised" to self-isolate for 14 days.
The game at Rugby Park is due to take place on Friday night but all home players have been told to stay away.
It follows Kilmarnock confirming a further three Covid-19 cases on Thursday night after three positive tests earlier in the week.
The SPFL is due to discuss the fate of the fixture later today.
There is also a doubt cast over Kilmarnock's next two figures - away to Falkirk and at home to Dunfermline in the Scottish League Cup - which fall within the self-isolation period.
A statement from the Scottish FA and SPFL joint response group said: "NHS Ayrshire & Arran Test and Protect Team carried out Covid-19 contact tracing following the six confirmed positive tests at the club.
"As a result, the club has been advised by the local Problem Assessment Group that the whole playing squad should self-isolate for a 14-day period. This is in order to minimise the risk of further cases in the staff group and wider local community and to support Test and Protect."
On Thursday, manager Alex Dyer said his squad were "in limbo".
Dyer said one of the initial three players to test positive felt unwell on Sunday after the victory at St Mirren the previous day, and was not allowed to train. The other two have been asymptomatic.
"We thought it was just a bug because of the changing of the weather, then we found out three players tested positive," he explained.
''We won't feel sorry for ourselves - it's part of life. We'll train when we are allowed to and do all the things we can. If they let us play the game we'll do the best we can."