Not only is Maika Sivo's season over but he could miss the beginning of the 2022 NRL season after scans revealed a ruptured ACL and damaged MCL for the Parramatta winger.
The Eels edge weapon's right knee was twisted in a tackle in Saturday's 32-16 win over North Queensland.
Initial hopes were he could recover quickly enough to feature in the finals.
Instead the 27-year-old Fijian requires surgery, a club statement on Tuesday read, conceding a delayed return next season was likely.
He joins teammates Reed Mahoney (shoulder) and Nathaniel Roache (knee) on the long-term injury list.
Off-contract veteran Blake Ferguson is fit again though and likely to replace Sivo, while Reagan Campbell-Gillard is on track to return from a groin injury during the NRL finals.
The Eels' (sixth, 14-8) defeat of the Cowboys kept their top-four hopes alive despite their late-season form struggles.
But they have the toughest run home with matches against top-two standouts Melbourne and Penrith to come.
