Josh Eaves, Tom Nisbet, Nico Rizzelli and Sam Royle have all signed new one-year deals with the club.
Eaves, Nisbet and Rizzelli all featured for the Super League champions this year, while 20-year-old Royle was the Academy player of the year in 2019.
Head Coach Kristian Woolf said: “It has been a tough year for these men. They have trained with us all year and been a big part of our preparation and success you see on Friday night.
“Some of these blokes have played one game all year since March which is tough, but they have helped us get that success so this is a reward for their attitude and work ethic they have shown and the qualities they have shown all year in tough circumstances.
“They have shown they are ready and we are looking forward to those blokes progressing into playing into some more first grade for us next year.”