Utoikamanu was named among a 38-man squad for Kristian Woolf's side, placed alongside Tigers teammates Joe Ofahengaue and Starford To'a, as well as NRL stars Moeaki Fotuaika, David Fifita and Jason Taumalolo.
But while Mate Ma’a Tonga's forward pack depth is sure to aid their prospects at the World Cup, Utoikamanu won't feature for the Tier 2 nation.
“It’s just that after the year I’ve had I need to spend as much time as I can getting my strength levels back up," Utoikamanu said in a club statement. "This is my priority right now.”
“I’ve been working hard in the gym for a while now, but I haven’t been able to do any of the real heavy stuff.
“Soon I will be able to lift the intensity with the weights and then be at the right level of strength when the squad comes back together in November.
“I’m due some luck on the injury front, that’s for sure."
Ankle and wrist injuries hampered the 22-year-old throughout this year, with Utoikamanu playing just the nine games for the Tigers in 2022.
The additions of Isaiah Papali'i and Apisai Koroisau are sure to bolster the Tigers' hopes of a top eight return in 2023, while Utoikamanu's health is sure to be a key factor in the club's success next season.