St Helens and Castleford have both postponed their weekend fixtures under Covid-19 protocols.
St Helens had been set to host Hull KR on Friday, while the Tigers were supposed to be travelling to Catalans Dragons on Saturday.
As a result of the postponements, Hull KR will now travel to Catalans on Saturday instead.
Saints and Cas have been permitted to postpone the games as more than seven of their top 25 players have been required to isolate either because of a positive test or as a close contact.
“The growing number of postponements, while reflecting the prevalence of Covid-19 in society, is a major concern for rugby league as for other sports,” the RFL’s chief regulatory officer Karen Moorhouse said.
“In that context, Hull KR’s willingness to rearrange their away match against Catalans Dragons is an example of the flexibility that served the sport so well through 2020, and which may be required over the coming weeks and months.”
The double postponement takes the tally of called off or cancelled fixtures in Super League this season to 14.
For the second successive season the table will be decided by a winning percentage.