Surprise reports emerged earlier this week regarding the future of Sydney Roosters centre Joseph Manu, linking him to a short-term stint in Japanese rugby.

It's certainly not the first - and won't be the last - time an NRL star has been linked with an overseas stint in the 15-man game, whether that be in Japan or France.

The money is simply outrageous. On a per week or month basis, it's even more than what Rugby Australia were able to pay Joseph Suaalii to make him the face of the sport at home from the start of the 2025 season ahead of the British and Irish Lions tour, followed two years later by a World Cup to be held down under.

And money talks. Ultimately, that is why players have gone overseas before, and will continue to be linked with it into the future.

But the suggestion for Manu's move to Japan is one has the potential to open a can of salary cap eating worms.

The star centre, who is well known to want to play fullback, is off-contract at the end of the 2024 campaign with the Roosters. While the tri-colours are confident he will never play NRL against the club, there is the threat of that happening, with the St George Illawarra Dragons leading a list of interested clubs.

It's believed at this stage that the Dragons are the only rival club to have a formal offer on the table, although that totals well over a million dollars per season.

The Roosters, while having plenty of cash to splash for Manu, are believed to be unable to match up financially to the Dragons' bid given some of the signings and retention work they have done in recent times.

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Neither Spencer Leniu (who was actively being pursued by the Canterbury Bulldogs before signing with the Roosters) or Dominic Young have come cheap, and they have re-signed a long list of players on upgraded deals in recent times including boom youngsters Sam Walker and Siua Wong.

If you're looking for evidence of the Roosters' tight salary cap, then the fact they could only re-sign Billy Smith to a one-year deal, despite the youngster being earmarked as a long-term future prospect in the Roosters' centres, is right there ready to smack you in the face.

But that's the point of the salary cap - to keep the competition fair and even. The effectiveness of the salary cap in doing just that has been debated ad nauseam, and you could certainly point to the fact it hasn't really done the job all that well.

That said, it could be a lot worse.

Just look at the English Premier League in the sport of football, where there is no salary cap. Aside from Leicester City's stunning title in 2016, either Manchester City, Liverpool, Chelsea, Arsenal or Manchester United have won every title dating back to 1996.

Blackburn Rovers were the last club outside Leicester and the big five to win a title, way back in 1995.

And while the NRL have usual competitive suspects - the Melbourne Storm, Penrith Panthers, the Roosters themselves - none have had that long of a reign of dominance. With the exception of the Wests Tigers, every NRL club have made the finals at least once in the last decade, and 13 clubs have won a competition since 2000.

Given two of the current 17 didn't even exist in 2000, that is a fairly impressive spread of success, and something not seen in competitions without a salary cap.

But by allowing Manu to go ahead and earn a full NRL season's wage in Japan, before returning to the Roosters, you bring into question the integrity of the system, even if it isn't perfect.

What's more, there is a precedent for this sort of thing. The NRL have knocked back other players, most notably Benji Marshall, from doing something similar in years gone by.

The precedent also has the Sonny Bill Williams situation to explore, where he rejoined the NRL in late-2020 after the Toronto Wolfpack (where he was at the time) collapsed, however, that was with just a handful of rounds remaining, and came after he was in rugby league, and not as part of a planned manoeuvre.

The NRL are yet to pass public comment on Manu's situation, but they will need to approve any return for Manu if he does spend the first half of 2025 overseas in rugby union.

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I'm not sure what the answer is though. Manu is the type of player who the NRL don't want to lose, so him playing half a season is better than none, but the old saying, that no one player is bigger than the game, must ring true to an extent here.

There are, and always will be, other stars, other players ready to take the limelight for every player who moves to rugby union.

Let's be real here - this isn't about rugby league against rugby union.

It's not about the 13-man game being scared of the 15-man game. Blocking any move for Manu to skip half an NRL season to earn a full year's wages in Japan before returning to collect another is about the integrity of the salary cap.

It's about ensuring the NRL financial rules do the job they were intended to do.

If Manu signs a deal for less money with the Roosters than he can gain elsewhere, then that's what it must be.

Not topped up by another million dollars from Japan.