Catalans' Super League game against Wigan on Saturday has been postponed after three players from the French club tested positive for Covid-19.
A non-playing member of staff also returned a positive test on Tuesday.
Two of the unnamed players featured in Saturday's Challenge Cup sixth-round win over Wakefield.
Two Trinity players are required to self-isolate after test and trace analysis, but at this stage their game with Warrington on Sunday remains on.
Wigan will now play Castleford, who were due to be without a fixture this weekend, at Warrington's Halliwell Jones Stadium on Saturday.
This is the second example of coronavirus cases at a club causing disruption to the Super League schedule since the season resumed on 2 August.
Several Hull FC players tested positive for Covid-19 earlier this month, leading to the postponements of Super League fixtures involving the Black and Whites and also Salford, who Hull had played in the days prior to the positive tests.
Meanwhile, St Helens have said a non-playing member of their staff who tested positive last week has since returned four negative results.
Revised Super League schedule for 29-30 August
- Wigan Warriors v Castleford Tigers (Saturday, 16:15 BST)
- Leeds Rhinos v Salford Red Devils (Saturday, 18:30 BST)
- Hull KR v St Helens (Sunday, 13:00 BST)
- Huddersfield Giants v Hull FC (Sunday, 16:15 BST)
- Warrington Wolves v Wakefield Trinity (Sunday, 18:30 BST)