Salford Red Devils finished fourth in Super League after St Helens outclassed Wakefield Trinity at Belle Vue.
Cameron Smith has only suffered a minor shoulder injury, while Billy Slater will be monitored after being knocked out cold.
Matt Dufty shone in his first NRL appearance for St George Illawarra Dragons, who hammered Manly Sea Eagles, as Parramatta Eels also won.
Club captain Paul Gallen has signed a one-year contract extension with the Cronulla Sharks.
Greg Eden scored 34 tries for Castleford in Super League this year but Jy Hitchcox stepped up in his absence with a double against Catalans.
NRL referees chief Tony Archer says Sia Soliola should have been sent off for his high challenge on Melbourne Storm's Billy Slater.
Melbourne Storm are two points clear at the top of the NRL standings following a 20-14 victory over Canberra Raiders.
Leeds Rhinos were held to nil for just the second time in Super League, with Wigan Warriors securing a confidence-boosting 34-0 victory.
Sydney Roosters and Cronulla Sharks stayed on course for top-four NRL finishes with victories on Friday.
After being hit with a long ban, Leigh Centurions' Jamie Acton said he "let everyone down" when he picked up an injured Greg Bird.