Manly hooker Apisai Koroisau.

The rise of Manase Fainu has inevitably led to the fall of Api Koroisau as the Fijian international prepares to leave Manly.

And the 26-year-old is fully aware of the circumstances – even embracing the fact he's played a part in Fainu's rapid improvement in just 32 NRL games.

"A hundred per cent … these young players coming through, this is what happens. It's a business and the salary cap pressure is a real thing," Koroisau said.

"You've just got to roll with the punches and do the best you can."

But before anyone organises his farewell party, Koroisau has an elimination final to play against the Sharks this weekend, and then he's planning on a semi-final the following weekend.

Hopefully his last game at Manly will be like his last for the Rabbitohs in 2014 before he left for Penrith in the off-season.

Koroisau was plucked by then-coach Michael Maguire and placed in the No.9 jersey to replace Issac Luke in the NRL grand final against the Bulldogs after the Kiwis rake was suspended for a high tackle on then-Roosters second rower Sony Bill Williams.

"That was special circumstances … to be joining the team that last game. It's a bit hard to look forward too much," said Koroisau before a Sea Eagles session on Tuesday.

"I'm taking it a week at a time but I definitely want to leave on a high."

Coincidentally, Koroisau is heading back to the Panthers for a second stint in 2020.

"Manly is a place that has welcomed me with open arms... it was a hard choice," Koroisau said of the past four years and 75 games with the Sea Eagles.

"But it's probably Ivan [Cleary] more than anything," he said in explaining why he chose Panthers over a few good offers.

"I had a good relationship with him when I was at Penrith. He's a great coach and a rally good guy. That's under-estimated in the game – how good a bloke a coach is.

"To have someone like that and those [Panthers Academy] facilities as well is something I can use to take myself to the next level."

As for Fainu, Koroisau will miss his friendship and work ethic. He also thinks the Sea Eagles have a future captain-in-waiting in the 20-year-old.

"He can do anything to be honest. He's probably the best young hooker I've seen in a long time. It's amazing the way he plays his footy," Koroisau said.

"I've seen him come through the ranks the last few years and you just knew he was going to be special. He has the strength of a front-rower and has one of the best offloads in our team actually.

"Him as a leader is unbelievable. He's young and he's out there talking to everyone regardless of how many games they've played or how they stand in the rankings.

"The leadership quality is usually taught or gained over a long period of time. Manase has come through barely 30 games and he's ready.

"He's very game aware and it's very natural."

Sea Eagles hooker Manase Fainu.
Sea Eagles hooker Manase Fainu. ©Grant Trouville/NRL Photos

In another twist of fate, the rumour mill has Luke possibly linking with Manly in 2020 after he bid the Warriors farewell this season.

"If there was someone I'd back to have another year it would be him. He took me under my wing when I got to South Sydney, when I was a really shy kid," Koroisau said of Luke.

"He pulled me aside and made sure I was a part of everything and he pushed me as hard as I could go."

Fainu reckons Koroisau should look in the mirror.

"He's taught me so much… he has been so good to me…  I will miss him."