Kangaroos captain Cameron Smith is still getting his head around Jarryd Hayne’s decision to vie for a NFL career ahead of the Four Nations campaign.

Life after Jarryd Hayne officially began on Friday when the Kangaroos assembled in Brisbane for their Four Nations campaign – with captain Cameron Smith seemingly still getting his head around it.

While Australian coach Tim Sheens claimed Hayne’s sensational decision to try his hand at NFL had reinvigorated his squad, Smith was left wondering what might have been.

Apart from the shock value, Hayne’s withdrawal was another blow to an Australian squad that now boasts 11 rookies.

“I was pretty shocked, to be honest,” Smith told AAP when asked about Hayne’s decision.

“But you are never going to hold back one of your peers to do something that they believe in – good luck to him.

“It is disappointing to lose such a great player.

“Unfortunately, it is happening more and more often these days.

“But we are not going to sulk about it.

“The challenge is now to get those young blokes to understand what it means to play for Australia.”

Smith did not believe Hayne’s massive call would have a knock-on affect in the NRL.

“What he has done is a pretty big risk,” he said.

“He has freakish talent and physical attributes; not everyone can do what he does.

“I don’t think we will have 10 guys in the next couple of years trying out for the NFL.

“I think everyone has to understand it is a huge risk, what he is doing.

“But it is not a spur of the moment decision for him.

“Let’s hope we don’t see more of our elite players switching sports.”

Sheens tried to put a positive spin on Hayne’s departure.

“I think it has reinvigorated the team, let alone the public, who will now say ‘I want to have a look at this’ because there are new faces,” he said.

“We have still got a good core of seniors with 15 or 16 (having) played Origin and, if you have played Origin, you can play Test match footy.”

Asked how big a blow Hayne’s departure was to Australia’s Four Nations campaign, Sheens said: “Time will tell.

“But he is a quality player and we didn’t want him out.

“But he has an itch to scratch.

“In the meantime, it ensures a young bloke is closer to a starting spot.”

Sheens is expected to name a new-look Kangaroos team on Monday ahead of their Four Nations opener against New Zealand at Suncorp Stadium on October 25.