Sir John Kirwan has sent a warning to Kalyn Ponga about the reported $4.5 million contract offered to him which features an All Blacks clause, saying the NRL star will need at least two years of rugby experience if he wants to don the black jersey.
The Knights reportedly offered Ponga the large deal last week and it features the option for Ponga to leave the club for a season to pursue a spot in the All Blacks' 2023 Rugby World Cup squad.
But Sir John told the Sydney Morning Herald it'll take more than a single season for Ponga to find his place in rugby union - and he has the experience to prove it.
Sir John was head coach of the Blues in 2014 and led the recruiting of another NRL star, Benji Marshall, to join them at the Auckland franchise.
The move proved to be a failure, with Marshall not even surviving a full season at the Blues before switching back to rugby league.
Sir John said there were lessons for both himself and future potential code-swappers in Marshall's venture and hopes Ponga sees them before making his move.
"Benji just needed more time in the game and, sadly, I didn't have that time in the game," Sir John said.
"He would have been fine had he come over earlier and I was able to give him more time in the saddle. But we started losing and then all of a sudden you find yourself under pressure and I had no time to give him the attention and time he needed.
"In the end it was a mutual decision that 'This is not working out'. I was really about it to be honest, because I felt the situation let him down."
With that in mind, Sir John says he believes Ponga will need at least two years to adjust to rugby union if he wants a crack at making the All Blacks.
"I don't think he could do it in one year," Sir John said.
"It would be high risk on his part. He could take that risk if he wants, but this All Blacks team has some guys who are pretty big competitors and like to succeed. I think he needs two years. He's got nothing to lose. A two-year contract and if it doesn't work out he can go back to league.
"This has nothing to do with money. For guys at this level, what I've realised is that they want a different challenge. I believe that's what Kalyn wants, and if he wants to have a crack then it won't be about money. He's got the ability man, for sure. He's got the ability, he just has to decide which position and I think he's more a 10 or a 15."
Sir John added unlike Marshall, Ponga had a few factors on his side.
"It's better do it when you're younger, and you've got a background in the sport, which Kalyn ticks both boxes. Guys who have played rugby at school, guys like Solomone Kata, who is now on the wing for the Brumbies ... it's going to be a lot easier.
"I'm pretty sure if Roger [Tuivasa-Sheck] wanted to come over it would only take him a couple of games and he'd be all good."
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