Liam Martin's Panthers contract expires at the end of next year, and Brisbane and Cronulla are monitoring his situation.
News Corp reports both clubs are interested if the Kangaroos forward becomes available from November 1.
Martin, 29, paused contract discussions with Penrith in August. His management has reportedly asked the club to pay him $1 million per season.
He wants a three-year extension, but Penrith also needs to secure new deals for co-captains Nathan Cleary and Isaah Yeo, as well as Moses Leota.
Cleary and Yeo are the Panthers' main contract priorities, while Martin is understood to rank ahead of Leota among the club's intended re-signings.
Penrith is disciplined in its salary-cap management, adding pressure to negotiations over Martin's asking price.
"I'm hoping that there's a spot for me here and obviously there's a long gap until November 1, so we'll have to wait and see," Martin said last month.