St Helens hooker James Roby has been ruled out of Friday's World Club Series match against Sydney Roosters.
The former Man of Steel missed last week's defeat at Salford with a rib injury and has failed to recover in time for the clash with Trent Robinson's men.
Travis Burns and Dominique Peyroux have been added to Keiron Cunningham's 19-squad, while former Wigan wing Joe Burgess is poised to make his Roosters debut.
"It is a huge game for the club, Super League and the players here," said Jon Wilkin. "The younger players in the squad look up to the NRL and the calibre of player here.
"But these NRL players are just human and a good performance would be huge in terms of the development of our players.
"I'm excited about the series and I'm sure they will be keenly contested matches. The NRL respect what we do as they are scouring our comp for talent.
"We want to show our younger players that our comp has merits and strengths and they can play here rather than over there."
St Helens: Kyle Amor, Travis Burns, Theo Fages, Joe Greenwood, Morgan Knowles, Louie McCarthy-Scarsbrook, Tommy Makinson, Jack Owens, Dominique Peyroux, Greg Richards, Andre Savelio, Adam Swift, Lama Tasi, Luke Thompson, Jordan Turner, Atelea Vea, Alex Walmsley, Luke Walsh, Jon Wilkin.
Sydney Roosters: Aidan Guerra, Blake Ferguson, Brendan Elliot, Dale Copley, Daniel Tupou, Dylan Napa, Ian Henderson, Isaac Liu, Jackson Hastings, Jake Friend, Jayden Nikorima, Joe Burgess, Kane Evans, Latrell Mitchell, Mitchell Aubusson, Mitchell Frei, Sam Moa, Shaun Kenny-Dowall, Siua Taukeiaho, Tyler Cornish, Vincent Leuluai.
Watch St Helens v Sydney Roosters live on Sky Sports 1 HD on Friday from 7.30pm. Catch the match for £6.99 on NOW TV. No contract.