Dylan Lucas is expected to provide a bench lift for Newcastle after returning from an ankle injury last week.
He told CODE Sports he came back four weeks earlier than expected, using ice and cream at home to reduce swelling and restore movement while seeking advice from club medics.
"pretty much just sitting in the ice machine," he told Code Sports.
Lucas said it was about six weeks into his recovery before he considered a finals return realistic.
Penrith's gamble is to begin their match with Jack Cogger at halfback and superstar Nathan Cleary on the bench, available if needed.
The plan would let the Panthers pursue a grand final place while giving the reigning Wally Lewis medallist more rest, despite his foot injury.
Coach Ivan Cleary said on Saturday that Nathan was "ready" but acknowledged the injury "could get worse".
"He'll be ready. He's done a bit of everything," Cleary said.
"He's actually living with us at the moment, so I've actually seen it firsthand how much he's actually done. It's crazy. He's left no stone unturned."
Liam Henry and Scott Sorensen will start, with Lindsay Smith and Isaiah Papali'i shifted to the bench.
The changes point to Penrith prioritising early defence before using Smith and Papali'i as attacking options near halftime.
The selection call has given Newcastle a chance to pursue a shock grand final berth.