Peachey will play centre in Saturday night's clash with former club Wests Tigers, set to replace Izack Tago as he begins a six-week recovery from a pectoral strain.
There were suggestions on Thursday the Panthers could rest several players in Bathurst, but officials have told AAP that is not the case and halfback Nathan Cleary is in no doubt after fighting through a groin strain last week.
Regardless, Peachey is well aware his chance has come to secure a first-grade spot at Penrith.
An Origin player when he left the club in 2018, he endured a difficult three years at Gold Coast before a horror 2022 at the Tigers.
It prompted him to sacrifice close to $100,000 and end his Tigers deal early to return to the Panthers, as part of an off-season player swap with Charlie Staines.
Peachey has played one NRL game off the bench this year, while acting as a utility in NSW Cup in other weeks.
But he is now confident he can rediscover his best on returning to Penrith's starting team, after watching with pride in recent years as several of his former teammates developed from youngsters into the game's best.
"I definitely believe that," Peachey told AAP.
"I put myself back in the environment I was in when I was playing that kind of football.
"And I wasn't around the players that I am with now. We didn't have that kind of talent.
"Just to be involved in this team, see Yeoy (Isaah Yeo) and Nathan (Cleary) and Jarome (Luai) and Fish (James Fisher-Harris) do the stuff they are doing now is pretty cool.
"I just want to prove to everyone that I can get to that level."
Peachey, now aged 31, is adamant he did not have a point to prove against the Tigers, after he spent half of last season playing in their reserve grade side.
He was well aware he would start this year in NSW Cup too at Penrith, and have to fight his way back into the NRL.
But he believes the football he has played this season is his best in years.
"It's probably the most consistent I have played since 2018," Peachey said.
"Gold Coast, I had three years up there, and that was a bit on and off. We didn't win many games.
"I went to the Tigers last year, which was really hard to be involved in. I was probably in the worst shape of my life. Mentally just wasn't really engaged in playing football.
"I just wanted to test myself coming back to Penrith and give myself the chance to play good football again."
