Bula, a former promising basketball player, impressed the Tigers coaching staff with his efforts in the Jersey Flegg Cup, spending the 2023 pre-season training with the NRL squad.
New recruit Staines meanwhile is reportedly being considered as a winger heading into 2023, training at both fullback and wing after his 2022 move from Penrith.
The 22-year-old played 15 games for the Panthers last season, scoring three tries after a breakout 2021 season.
Sheens, speaking to The Herald, revealed that he is expecting a big year from Bula and won't be afraid to use him if he proves he's good enough.
“Jahream Bula will be a kid who comes out of nowhere,” Sheens told The Herald.
“Daine has been training at halfback and fullback, ‘Stainesy' at fullback and wing, but this kid has been playing fullback all year in the second team. And he has been the best trainer at the club.
“I'm not afraid to throw blokes in, and if they're good enough they're old enough.”
The Keebra Park product has earned plenty of praise for his athleticism early in his career, with Junior Titans System coach Jamie McCormack looking back on Bula's time with the club as a junior with applause.
“Sometimes when we do junior recruitment and talent scouting it's great to keep an eye out for genuine athletes,” McCormack said.
“Whatever skills they may be deficient in, that's our job to make sure they improve.
“Jahream is just an athlete – for an outside back coming from a basketball background, the ability to jump high in the air and catch balls above his head (is helpful).
“His athletic ability and power base to get high off the ground gets him into try-scoring situations.”