Aloiai was set to square off against Gallen in Newcastle on December 10 and called in sick to a promotional photo shoot on Tuesday.
Manly’s entire NRL squad is yet to be fully vaccinated but it’s unknown whether Aloiai had been inoculated against Covid.
The NRL has not mandated the vaccine, meaning the 29-year-old is free to play under league regulations.
Fox Sports understands Joey Leilua, who was training with Aloiai and due to fight on the card, may have tested positive several days ago and Aloiai also received a positive result on Wednesday morning.
