All Blacks: Steve Hansen says Ma'a Nonu's 'brave' 2019 Rugby World Cup dream is still alive

All Blacks coach Steve Hansen has revealed that Ma'a Nonu's extraordinary comeback attempt remains alive and that he is still in the mix to attend another Rugby World Cup.

Hansen described Nonu's return to the Blues and goal of making another World Cup four years after his last test as "brave" and said the selectors would have some difficult decisions to make around the make-up of the midfield if the veteran's good form continued.

Nonu will turn 37 next month and the odds of him adding to his 103 test caps appeared to lengthen when he wasn't named in the foundation day squad who met today in Wellington today minus the injured Sonny Bill Williams and Damian McKenzie, the latter's dream of going to Japan in September dashed by a serious knee injury.

However, Hansen said an agreement with New Zealand Rugby and the five Kiwi Super Rugby franchises around the foundation days – another will be held in Auckland on May 20 for the North Island players and in Christchurch on June 3 for the South Islanders – meant only those involved with the All Blacks last year could be included.

The reason for that was "so they [New Zealand franchises] could do some clear planning and would have an understanding of who they would have and who they would not have", Hansen said.

"There are some guys that aren't here, that if you were picking on form probably would be here. The rules are the rules and we're all playing by them."

As the squad, minus McKenzie, who was a late withdrawal and plus Chiefs prop Atu Moli, a late inclusion, assembled in Wellington, Hansen was asked about the form of Nonu, who scored two tries for his side in their narrow loss to the Chiefs in Hamilton, his first coming after he ran over the top of midfield rival Anton Lienert-Brown.

It was a continuation of a remarkable run of form from Nonu after his three seasons in France. A week earlier at Eden Park he scored a long-range try against the Waratahs.

"He's just being Ma'a, isn't he?" Hansen said. "You get the subtle touches and you get the brutality, as ALB [Lienert-Brown] found out at the weekend.

"None of us knew what he would come back like. I just like the fact that he's been brave enough to come back and he'll be considered like everybody else.

"We know he can play test rugby, he just has to show that he's got the ability to do that on a weekly basis at Super Rugby level and then we have to make hard decisions. As someone pointed out, there are a lot of good players in that position so there will be good people who miss out."

Williams' absence from Wellington after he had keyhole surgery on his right knee last Friday wasn't a big concern, said Hansen, who added there was still plenty of time for the big midfielder to return for the Blues before the All Blacks' first test of the year against Argentina in Buenos Aires on July 21.

The All Blacks will play five tests before their first pool game of the World Cup, a test against South Africa in Yokohama on September 21.

Several other players are making their way back from injuries, including loose forwards Sam Cane and Liam Squire, prop Owen Franks, and halfback Aaron Smith.

The late inclusion of Chiefs prop Moli, who is primarily a tighthead but can play loosehead too, could be an insurance against the loss of veteran Franks, who is in his final year with the side.

"He [Moli] is a player that we're really interested in and we just want to see where he's at," Hansen said.