Sydney Roosters speed conditioning coach Hayden Knowles defied the risk of being laughed at to say former NRL superstar and San Francisco 49ers trialist Jarryd Hayne had the talent to be an Olympic track athlete.

And Hayley Butler, who attended the same school as Hayne in Sydney's western suburbs and was selected to represent Australia in the 100m hurdles at the 2010 Commonwealth Games, supported the claim.

Hayne has made a huge impression on the NFL with his athletic prowess and the ability to play a variety of positions in what's essentially a specialised sport. However, Knowles, who mentored the-then teenaged Hayne when he was a member of Parramatta's coaching staff recalled how athletics was the emerging football star's sporting passion in 2007.

"People will read what I believe and ask what kind of drugs I'm on but they'd be the same people who thought that when I said he'll be an NFL player," Knowles said. "I don't know how people could doubt anything any more - if Jarryd wanted to do anything [sporting wise] he could.

"Athletics lost out as a sport when he was 16 and was very passionate about it but no one took him under their wing and said 'come on, you're going to the Olympics'. No one really embraced the passion he had back then.

"However, people embraced his footy passion and the 49ers are clearly embracing his passion for the NFL. However, he was genuinely passionate about athletics.

"His mother Jodie was an athlete, he did the Little Athletics like a lot of other footballers do when they're kids, and his background put him in good stead.

"He could have been an Olympian and I don't know how, after what he's done, anyone wouldn't believe Jarryd couldn't do anything if he put his mind to it."

One person happy to support Knowles' view of Hayne - who was invited to train with Usain Bolt in Jamaica after the pair met at a celebrity race in Sydney five years ago to celebrate the 10th anniversary of the Sydney Olympics - was Butler, who is training to qualify alongside Olympic champion Sally Pearson for next year's Rio Games.

Butler was two forms above him at Westfields High School but remembered when he won the 100m hurdles at a major championships after limited training with the athletics squad.

"He was a freak," she said. "He'd never trained before but he was such a natural.

"You can see from what he's achieved that he just has 'it'. I'm guessing he did Little Athletics as a kid because he was a fluent runner and technically correct.

"He turned up to training and won either the state or national championships. To have made it in athletics all Jarryd would have needed to do was sharpen his skills and train hard.

"He could have gone really far and what we've seen in American football is that he builds on that base. He is quick, can pick up skills quickly ... he's just a phenomenal athlete."