Coach Jim Tomsula has refused to confirm whether The Hayne Plane has been cleared for takeoff against the Minnesota Vikings, with seven players on the 49ers roster to miss out on the Week 1 blockbuster.
Hayne's athletic ability was never questioned during his NRL days but his work ethic was a contentious topic.
The 27-year-old didn't exactly embrace training whilst at the Eels but he has been given no choice at the 49ers and the army-like training regime has served Hayne well so far in his NFL odyssey.
"I definitely knew my body was more adapted to the grind of NFL, to the way it’s played," Hayne told the Daily Telegraph.
"And that's been my biggest advantage, being able to adapt straight away.
"Having an endurance background from rugby league but also having the explosiveness that came with it."
Hayne did minimal weights during his rugby league days but has transformed from a relative weakling in the gym to above the NFL average.
"For me, I get through sessions here a lot better," he said.
"Still, it's quite different on the joints, a lot harder because of the amount of force we put through our body.
"At one stage we trained eleven days straight. That was some of the craziest stuff I’ve ever done – it was unbelievable.
"It felt like I was in an army camp again it was so full on. We were literally running routes for eleven days straight. That stuff gets you fit.
"I'd only had surgery four weeks earlier too so I was still getting conditioning to come back from that."