Averillo, who played in his final game as a Bulldog on Sunday afternoon against the Gold Coast Titans, was taken from the field in the final ten minutes of the walk, hobbling from the field of play with club trainers and medical staff.
Immediate fears were expressed by club medical personnel over a possible ACL injury, although that was later softened to a potential PCL injury.
Averillo will need scans to confirm the extent of the damage to his knee. If the injury turns out to be an ACL tear, it could all but end his 2024 season before it starts, while a PCL would likely disrupt the start of pre-season, but leave him able to return to training prior to the Christmas and New Year break.
The back, who has been used everywhere from the centres to fullback and the halves during his tenure with the Bulldogs, earlier this season agreed to switch to the Dolphins ahead of the 2024 season, with the Bulldogs already having signed the likes of Stephen Crichton and Bronson Xerri to bump up their struggling side and backline for 2024.
Dolphins coach Wayne Bennett struck to land the signature of the talented back, who played some of the best football of his career to date in the centres earlier this year.
The Dolphins have had an enormous injury toll for much of their first season, and losing Averillo for any length of time would be yet another blow to the Redcliffe-based outfit as they head into their second season as an NRL club.
Averillo's role at the Dolphins next year remains to be seen, with the expansion franchise also signing Herbie Farnworth to join next year, ramping up competition for spots in the backline.