Katoa has returned to running after three head knocks in the space of 90 minutes prompted bleeding on the brain and seizure activity last year, while playing for Tonga in the Pacific Cup.
The 26-year-old was ruled out of this season last November, but the sight of him back running and assisting with coaching at training had offered hope for 2027.
But an emotional Bellamy indicated on Monday night any return was still far from guaranteed, with Katoa's welfare still the priority.
"I don't know whether he will play next year. I don't know if he will play again," Bellamy said on the Seven Network's Agenda Setters.
"The doctors haven't made that decision yet and I don't know when that decision will get made. I'd imagine after a certain amount of time he will have more tests and go from there.
"It was a major injury and we certainly want Eli to be able to live his life in a normal way ... but we'd love to have him back playing footy too."
Katoa has spent the past week in Tonga and Samoa, fulfilling what he labelled a boyhood dream to go back and speak with school children.
Last year's Dally M second-rower of the year has previously said he wants to continue ticking the required boxes, telling Storm fans on Instagram "In God's timing I'll be back soon" last November.
He has remained around Melbourne training as a mentor for second-rowers Joe Chan, Ativalu Lisati and Cooper Clarke, while also earning credentials to be on-field trainer.
"He's doing really well at the moment. He's coming in every day," Bellamy said.
"We've given him a little role with our edge back-rowers to take them under his wing, like young Cooper Clarke.
"Even Joey Chan and Valu. He's helped them out a whole heap as well. So that's the good news."
After copping a head knock in warm-up and being allowed to start a Test against New Zealand without an off-field HIA, Katoa was hit again in the first half of the match in Auckland last October.
He then returned to the field, before another head knock in the second half and Katoa suffered seizure activity while on the sideline after going off.
Three members of Tonga's medical staff have since been threatened with two-year NRL bans, while another was handed a formal warning.
