The NRL's biggest star almost never played the sport at the highest level.

It has been revealed on SEN Radio that, had the AFL's eligibility rules been different, Tom Trbojevic may have been a Sydney Swan instead of a Manly Sea Eagle.

According to the AFL's eligibility rules, players must be 18 years of age to sign with a club in any capacity. In the NRL, players are allowed to sign from 16 years of age, which gave Manly the edge in signing Trbojevic.

The Manly star, who is the odds-on favourite to win the Dally M medal despite having played just 15 games this season, has been one of the best in the competition, with his side barely losing a game with Trbojevic on the park.

Manly's future is looking bright thanks to Trbojevic, who also has two brothers in Jake and Ben at the club, with the youngest of the trio yet to properly establish himself in first grade.

Both Jake and Tom have turned themselves into representative players, but Matty Johns said it could have been very different.

“He was a guy at 14 or 15 years of age that the Swans recognised,” Johns said.

“They threw a lot of money at him, but his family are real rugby league people.”

Johns was referring to the Swans academy, who, like most AFL clubs seek to develop youth through their own systems, despite not being able to officially contract players.

Trbojevic has now played more than 100 games for the Sea Eagles, while he has also represented Australia and New South Wales since his club debut in 2015 as an 18-year-old.

The star 24-year-old is contracted to the Northern Beaches-based club until the end of 2025 on a reported figure over $1 million per season.