Dallin Watene-Zelezniak will put his hand up to replace Dylan Edwards at fullback for Penrith in their season-defining NRL clash with Manly on Saturday.
Edwards failed to return after halftime in Sunday's 16-14 loss to St George Illawarra, amid fears he had torn his medial cruciate ligament.
There were hopes after fulltime the tear was only a minor one, however, he will go for scans on Monday morning and will likely be ruled out of Saturday's final-round clash.
And Watene-Zelezniak, who moved to the back last week but hasn't played fullback consistently since 2015, said he would ensure he was ready for the task.
"I love playing fullback. But with Dylan, it's going to be massive shoes to fill," Watene-Zelezniak said.
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"I think I've just got to train there and get the feel for it again.
"I haven't played there for two years. The game changes in two years for positions.
"It's just some adjusting I have to do. If I happen to be there next week I have some adjusting to do."
The injury to Edwards would be a crucial blow for Penrith given captain Matt Moylan is already out injured.
It leaves 22-year-old Watene-Zelezniak as the only real option at fullback, while rookie Tyrone May continues to impress in the No.6 jersey.
Kiwi international Dean Whare is available and languishing in reserve grade, meaning he will likely receive a call up to fill the vacant spot on the wing.
A win will secure the Panthers' spot in the top eight, while they will need either the Dragons or North Queensland to lose if they are beaten.
