Once set for the top eight after seven straight mid-season wins, the Panthers need to win their last two games and have results go their way to play finals.

And they'll have to do it with one of their least experienced NRL teams in memory.

Penrith are preparing to debut their ninth players this season in Parkes junior and second-rower Billy Burns, with seven of the rookies set to turn out against the Roosters.

"It's the first must-win (NRL) game in my career. It's a major game against the Roosters at the SCG," rookie centre and Wellington Cowboys junior Brent Naden said.

"It's a very special ground for them and special game for us.

"It's a cricket ground and they are putting cricket scores on teams there."

Penrith's rookies all have one thing in common.

They've come through a prodigious junior system that has regularly fielded teams in under-20s and under-18s grand finals.

But the youngsters admit that experience means very little come the business end of the season in the NRL.

"It's completely different," Naden said.

"That's like junior football. There are big scores and there are always going to be standout kids coming through the juniors.

"But when you get to the big league you're like a small fish in the big pond again."

Another thing a number of the up-and-comers have in common is their Western Rams roots.

Burns comes into the side in place of another Group 11 junior Isaah Yeo.

Yeo underwent season-ending shoulder surgery this week, while his fellow Dubbo products Kaide Ellis and Matt Burton have also played in the NRL for Penrith in recent times.

By Penrith's own admission, the string of changes this year hasn't helped cohesion.

Burns will be the Panthers' 33rd player this year, more than any other club has used this year or last.

Burns will start from the bench on Saturday night.

The Panthers sat one point outside the top eight at the start of the round. The play Newcastle in the final round.