Jarryd Hayne says head 'rattled for days' after big hits as NFL rookie

Former NRL star Jarryd Hayne has revealed how two hits in his rookie NFL season left him "rattled" for days.

Back in Sydney during the off-season, Hayne said he needed to strengthen his neck in order to prepare for the bigger impact of the American game.

"Obviously the endurance side of things is different but I got hit twice head on and my head was rattled for a couple of days," he said.

"Definitely your neck has to get a lot stronger. It's pretty tough. It's like having a helmet and running through a brick wall. If you do that, you can make it in the NFL."

The 27-year-old played eight games with the San Francisco 49ers in his first season as a professional NFL player, but isn't guaranteed a return.

Franchise aren't permitted to talk with players for another two months, but the 49ers do hold his rights and can offer him a spot when team activities are organised for the end of April.

Hayne, who was used primarily as a punt returner under since-sacked coach Jim Tomsula, has planned a return to California at the end of March and aims to become a more versatile player.

"I like being out wide like a wide receiver. Running back's also very enjoyable as well. I think for me, it's just about being versatile and playing anywhere they put me," he said.

He was also willing to be used as a slot receiver, a position he experienced while training in opposed sessions at the 49ers.

"You've got to run every other play for the other team coming up that week and I actually did a lot of slot receiver, which I thoroughly enjoyed," he said.

"But for the coach, I've just got to stay fit and play wherever they want me."

Either way, a burning desire to complete his first career touch down has proven to be the ultimate motivation for coming back this year.

Hayne came close when he was being used as a running back against the New York Giants.

"I got close twice this year. I was devastated," he said.

"It was actually a route that I ran that if I had run it a bit different, I would've scored against Detroit. I come close, and then obviously that one against the NY Giants as well.

"Definitely next year, it has to be done. It has to be done."