Wakefield Trinity's Super League match with Leeds Rhinos on Thursday has been postponed after two players tested positive for coronavirus.
As a result, Thursday's match between Salford Red Devils and Castleford Tigers has been pushed back to an 8.15pm kick-off while Hull Kingston Rovers vs Wigan Warriors remains a 6pm kick-off - both live on Sky Sports.
On Wednesday, Wakefield confirmed two of their players came back positive for Covid-19 following the third set of tests in the last week.
The club cancelled training on Wednesday morning, and later announced Thursday's meeting with Leeds would not go ahead as scheduled.
"The Wakefield squad will have a further set of tests on Friday before a decision is made about their fixture against Hull FC scheduled for next Thursday (September 10)," a Wakefield statement added.
One of the players who tested positive was in action against Warrington Wolves at the weekend, while Wakefield said neither were deemed at risk following their Challenge Cup game against Catalans Dragons on August 22.
After that match, three Catalans players, one of whom was not involved, and one member of their backroom staff tested positive for Covid-19, with their match against Leeds on Monday subsequently postponed.
Meanwhile, six Warrington players have been required to self-isolate for 14 days following the Wakefield match, although the Wolves did return a full set of negative tests this week.
Karen Moorhouse, the RFL's chief regulatory officer, said: "In what are unprecedented and uniquely challenging circumstances for the sport, we should first recognise the importance of the health and wellbeing of the players and other staff, and their families, at the clubs who have been affected.
"Again, we have been forced as a sport to show our ability to move quickly to ensure we still have a programme of four attractive fixtures in the Betfred Super League - and again, we are grateful to the flexibility of the clubs involved, and of our broadcast partners, in agreeing to these changes at such short notice."