Katoa sat out the entire 2026 NRL season after a severe head injury while playing for Tonga in the 2025 Pacific Championships.
The head knock caused a bleed on his brain, and he spent weeks in hospital after continuing to play longer than he should have.
Independent doctors are assessing whether he can return, with a decision expected within three to four months.
Reports say he is due for scans within six weeks. The 26-year-old is understood to remain confident about playing again, though clearance is not assured amid tighter concussion standards across sport.
Even if approved to return, he could miss the start of the 2027 season because he may have little time back in full contact.
Melbourne are cautious but keen to have him back. Katoa had become one of the game's leading second-rowers by the end of 2025, when the Storm lost the grand final.
His absence contributed to a difficult 2026 campaign, in which the Storm missed the finals for the first time under coach Craig Bellamy.
Katoa has played 118 NRL games, including 72 for Melbourne, and is contracted through 2027. The Storm are likely to offer him a new deal if he is able to continue playing.