With teenage star Bradman Best sidelined with a fractured foot and the more experienced Tautau Moga not completely recovered from a hamstring strain, Tuala will start in the centres when the Knights trial against St George Illawarra at Maitland Sportsground.

The NRL trial will kick off at 5.30 pm.

Tuala, who played 18 NRL games for the Cowboys over the past three seasons, has looked impressive during the pre-season and a strong performance against the Dragons will go a long way towards securing the 21-year-old an NRL debut for his new club in the opening round.

Coach Adam O'Brien has named a squad of 34 but it remains to be seen if they will all get game time with the club's NSW Cup side also meeting the Dragons in the preceding trial.

Fullback Kalyn Ponga, utility Connor Watson and young prop Pasami Saulo will all be missing due to their All Stars commitments on the Gold Coast while prop Herman Ese'ese has not fully recovered from an ankle problem.

In Ponga's absence, Tex Hoy will start at fullback off the back of an eye-catching performance in the NRL Nines in Perth.

Assistant coach David Furner said he regarded trials as a "necessary evil" because of the risk of injuries but the chance to test combinations and the new systems put in place by coach O'Brien during the pre-season would show where the squad is at.

"I know Adam is keen for the trial," Furner said.

"Everyone is looking at the halves combinations at the moment. There's a lot of talk about the team's spine and [hooker] Jayden Brailey is new to the club so they're the combinations Adam and the coaching staff will look forward to just to see how they go."

TRIAL SQUADS:

Knights: Tex Hoy, Hymel Hunt, Enari Tuala, Tyronne Roberts-Davis, Gehamat Shibasaki, Edrick Lee, Matt Soper-Lawler, Starford Toa, Mason Lino, Kurt Mann, Mitchell Pearce, Simi Sasagi, Bayden Searle, Lachlan Fitzgibbon, Aidan Guerra, Brodie Jones, Sione Mata'utia, Jirah Momoisea, Jayden Brailey, Luke Huth, Chris Randall, Mitch Barnett, Jack Cameron, Mathew Croker, Tim Glasby, Zac Hosking, David Klemmer, Brandon Russell, Daniel Saifiti, Jacob Saifiti, Josh King, Matt Cooper, Dylan Lucas, Mitch Black

Dragons: Euan Aitken, Eddie Blacker, Adam Clune, Mathew Feagai, Max Feagai, Jackson Ford, Tyson Frizell, Luke Gale, James Graham, Ben Hunt, Jacob Host, Tim Lafai, Blake Lawrie, Hayden Lomax, Zac Lomax, Joe Lovodua, Corey Norman, Jordan Pereira, Mikaele Ravalawa, Jason Saab, Tristan Sailor, Shaun Sauni-Esau, Tariq Sims, Jayden Sullivan, Paul Vaughan, Brayden Wiliame, Tyran Wishart.