Wests Tigers finished 2026 in the bottom half after an encouraging start.
Forward Alex Twal called Jarome Luai's contract a distraction, but also blamed injuries, poor form and lost confidence.
Luai and Apisai Koroisau had helped improve the culture before Luai signed with the PNG Chiefs for 2028.
His player options enabled negotiations without Tigers approval; his 2027 option was scrapped before a one-year move to Parramatta Eels.
On SEN's The Run Home with Joel and Fletch, Twal said, "I think the Jarome situation was one thing that I guess was a bit of a distraction.
Luai's second-half form declined during the slump, although Twal said the team improved late without matching its early standards.
Benji Marshall's side faces pressure, with the coach potentially in danger if results do not quickly turn around.
Latu Fainu and Javon Andrews are options to replace Luai beside Adam Doueihi, who walked out late in the season.
Jake Averillo has signed but is expected to play centre.