Andrew Johns has issued a warning to Gold Coast Titans recruit Carter Gordon after the 23-year-old confirmed he would switch codes from rugby union to rugby league.
Inking a two-year contract with the Titans last week, Gordon, a member of the recent Wallabies World Cup squad, will play rugby league for the first time next season, having never played it as a junior.
While he has the obvious potential to excel in the NRL, it is unknown what position he will play or how his transition will go.
As he gets ready to undertake a new journey in the NRL, Immortal Andrew Johns has issued him a warning about the difference in fitness level and in regards to adapting his skills to the 13-man code.
"League players who have gone to union have said it looks the same, the skill set is the same, but it's such a difference," Johns said on Immortal Behaviour.
"The ins and outs and the nuances of when to move the ball, when to kick – it's a whole new game.
"It'll be a real challenge to understand what his role is to start with, and then work on his combinations.
"Another big area is fitness – it's a totally different fitness base. There's a lot of stoppages in union, where league it's all up and back and the ball can stay in play upwards of five minutes.
"First thing's first, physically he's gonna have to really rip in to training."
Following in the footsteps of former Wallabies teammate Mark Nawaqanitawase, Gordon's arrival to the NRL comes after the Melbourne Rebels closed its doors and will no longer compete in the Super Rugby competition.
A Nambour product, he has managed eight Test appearances for Australia in the 15-man code.
Unknown what position he will play heading into next season, Johns has backed Des Hasler to bring the best out of Gordon as either a five-eighth or lock forward.
"It's interesting where Des sees Carter, does he sees him as a five-eighth? He's not a full back, so five-eighth or lock," he added.
"Des would have done his homework – he'd know about the ins and outs of Carter, his strengths and weaknesses and what he needs to, and then the strengths and weaknesses of the other players."