The Panthers confirmed the NSW five-eighth had suffered a grade-two medial ligament tear during Saturday's get-out-of-jail win over the Gold Coast.
The club said he had been sidelined indefinitely and would not be back for the final three regular rounds.
He is now eyeing Week One of the finals as his earliest possible return.
Medial ligament strains generally take 3-6 weeks to heal, meaning he may not be back at all this year, should the Panthers go out in straight sets in the finals.