Hull FC have confirmed six players and two members of staff have tested positive for coronavirus, while another player is being retested after an inconclusive result.
Five of the players to return positive results featured in the 54-18 defeat to Salford Red Devils on Sunday, as did the player who must be retested.
Another player who was not in the matchday 17 and two members of coaching staff also tested positive.
All individuals have been instructed to quarantine until August 21 as per the national guidelines in England.
Salford are still awaiting the results of their weekly tests.
In a statement released on Tuesday confirming the news, the Super League said: "Public Health England, the Hull FC players and staff, and the Salford Red Devils club were informed of the situation this evening.
"Salford's routine weekly test results have not yet been received, but the RFL is now analysing Sunday's match to determine how many players from each team will also be required to self-isolate under the test and trace procedures that have been agreed with Public Health England.
"Announcements on the impact on forthcoming Betfred Super League and Coral Challenge Cup fixtures over the next two weekends will be made as soon as possible."
Hull and Salford cancelled their respective training sessions on Wednesday and it appears doubtful either of their Super League matches, against Castleford Tigers and Catalans Dragons, will go ahead.
The Super League only returned on August 2, nearly five months after the 2020 season was suspended due to the pandemic.