Panthers halfback Nathan Cleary.

Penrith will prioritise Nathan Cleary's signature next after tying up local junior Reagan Campbell-Gillard for the next six seasons.

Cleary is off contract at the end of the 2019 season but can begin negotiating with rival clubs from November 1.

It's no secret the Wests Tigers are possible suitors with his father Ivan at the helm, while Cleary's recent success at Origin level only puts further heat on the Panthers to retain their rising halfback.

But in the club's favour could be the long-term stability around Cleary's mates at the Panthers, who have signed deals beyond 2020.

Campbell-Gillard is one of those teammates, with the 24-year-old's recent deal tying him to the club until at least the end of 2024.

"Obviously that's something the club is working through and now that there's a lot of other guys settled here Nathan is one the club will want to work on as well," coach Anthony Griffin said on Friday.

"There's good stability here and the combination with Jim (James Maloney) now here and at rep level. That gives him some confidence about where the club is heading as well."

Panthers prop Reagan Campbell-Gillard.
Panthers prop Reagan Campbell-Gillard. ©NRL Photos

The Panthers trained on Friday with Denver Test players Dallin Watene-Zelezniak and James Fisher-Harris joining the squad for the first time since returning from the United States.

Despite describing the Test as "overkill" because of the timing of the scheduling, Griffin indicated the pair – and other representative players – would back up after last weekend's matches.

"We've prepared as well as we can. The danger is making sure that's as strong and good enough as we need," Griffin said.

"We saw with St George Illawarra it's a funny type of year. Your players aren't always with you and they're coming in and out of different systems.

"But they've all come back physically well and we had a really good day yesterday and need to finish that off today.

"At this stage, they all pulled up really well. They've done extra rehab and are in good spirits."

Griffin admitted the club would monitor Cleary, James Maloney and Tyrone Peachey after the Holden State of Origin series and said resting the NSW trio was an option before the Telstra Premiership finals.

Penrith have identified the Sea Eagles' clash on Saturday as crucial to maintaining their charge towards a top four finish.

"The draw is the draw. If someone needs a rest because of injury or we think they're burnt out ... we'll keep monitoring. But at the moment they're all pretty good," Griffin said.

"It's probably a couple of weeks after Origin where it hits them. Origin will be gone in a week or two and it will be down to business.

"For us as a club that starts after the break – that's tomorrow. There is 10 games to go and the level will go up," Griffin said.

"We've got to keep building towards that, tomorrow is really important for us."