Culley left the field with trainers in the first term after his right knee appeared to buckle in a marking contest against Richmond's Nathan Broad on Saturday, subsequently substituted out of the game.
The No.1 pick in the 2022 AFL Mid-Season Rookie Draft, Culley has played five games for the Eagles in 2023 with the club now confirming that the Rising Star's season has come to an end.
“Unfortunately, scans have confirmed the worst for Jai and he will miss the remainder of the season,” West Coast general manager of football Gavin Bell said.
“It is a terribly disappointing result for him and the club only nine games into his AFL career.
“We know Jai will attack his rehabilitation with the utmost professionalism and determination, and the club will support him through the process.”
The 46-point loss to Richmond on Saturday was the Eagles' seventh loss of the season as they continue to deal with a mounting injury crisis, with 17 players now unavailable on the club's injury list.
“We're getting challenged at the moment with availability, as much as we want to be consistent on the field and make no excuses," Simpson said post-game.
“Last week we took a step back – we sort of see the bits where we get overwhelmed as a real challenge to try and change.
“We've got to keep the glass half-full as much as we can, I know it's a challenging time for all our supporters as well … but we are on a journey, we are working really hard on development, getting our young players through the side, hit the draft right … it's just not going to be a quick fix.”