Even if Jarryd Hayne breaks into a “red-hot” Fiji squad, he’ll find it tough to succeed in Rugby Sevens at the Rio Olympics, according to Australia’s Jesse Parahi.

The 26-year-old Parahi is well positioned to know the kind of challenge the former NRL and San Francisco 49ers star will face in his ambitious quest to make the transition to the frantic seven-a-side game.

After debuting in the Australian Sevens team in 2010 and earning 33 caps en route to helping them qualify for the Olympics last year, Parahi headed to the NRL on a one-year contract with the Wests Tigers.

That experiment lasted just six months and even though he only played a handful of reserve-grade games, Parahi admits his transition back to the lung-busting Sevens format at last weekend’s tournament in Paris was harder than most people would expect.

“It’s been tough to be honest,” he told Sky Sports Radio’s Big Sports Breakfast on Thursday.

“Six months out of the game and I’m feeling like I fell behind quite a bit.

“So I think it will be pretty tough for Jarryd moving forward. And that Fijian squad is pretty red-hot.”

Parahi said that even though Hayne was a tremendous athlete, the differences between the NRL and Rugby Sevens would surprise him.

Of further concern, Parahi believes, is Hayne’s NFL-specific fitness based around quick bursts of power with often long rests in between.

“It (Sevens) is a completely different beast to the NRL and more so the NFL,” he said.

“It’s really short but you’re left out on your feet for 14 minutes but you’ve got to try and grit your teeth and get through that.”

Parahi also noted that the majority of the Fijian players who Hayne will be competing with for spots had been playing the abbreviated version of the game all their lives.