Gregor Paul: The battle for final two spots in All Blacks' World Cup squad

Waisake Naholo and Shannon Frizell of the All Blacks run out on to field. Photo / Getty

There is still the better part of a year until the World Cup and yet the All Blacks probably know 29 of the 31 players they will take to Japan.

There is not a huge amount of mystery hanging over this squad or much room for there to be a dramatic change of thinking.

In all likelihood, there are only a couple of spots deemed by the coaches to be open.

The area of uncertainty is the loose forwards where Liam Squire, Kieran Read, Sam Cane and Ardie Savea, barring injury, will be on the plane.

There remains a long list of potential candidates who could join them and next year's Super Rugby and Rugby Championship are going to be used as an extended trial to see who makes the most convincing case.

The door is open to Vaea Fifita, Matt Todd, Luke Whitelock, Shannon Frizell, Jordan Taufua, Dalton Papali'i and Jackson Hemopo.

Whether it is open to one or two of them will depend on whether the All Blacks opt to take three or four specialist locks to the World Cup.

In 2015 they went to England with only three and didn't actually have a specialist on the bench for any of their knock-out games.

It was a risk but one they felt they could take knowing that Sam Whitelock and Brodie Retallick would go the full 80 minutes as long as they avoided injury.

And if they were forced off, there was confidence in the likes of Jerome Kaino and Kieran Read being able to cover.

If the decision is made to take four locks – and they would be Retallick, Whitelock, Scott Barrett and Patrick Tuipulotu – then the last place in the loose forwards will come down to who the coaches think will give them the best mix of skills they are looking for.

Probably, they will be looking to take another blindside – a big ball carrier and destructive defender.

Frizell appeared to be their preferred option in that regard for most of this year but injury prevented Taufua from taking his chance.

Fifita could drive himself into the middle of the picture if he's able to impress on this tour and then enjoy an extended run in the No 6 jersey with the Hurricanes next year.

Those three, tough, are scrapping for the fifth loose forward spot.

Patrick Tuipulotu (L) and Matt Todd speak at an All Blacks press conference. Photo / Getty

If the All Blacks coaches feel it is going to be a fast World Cup with the key battleground being the tackled ball, then it is conceivable they will take six loose forwards in total and just three locks.

That would most likely mean Todd being in and Tuipulotu being out.

Obviously, injuries could and most likely will force a few changes but there really isn't much intrigue or uncertainty.

Perhaps Kane Hames can return from injury next year and force his way back into the propping pool, but it will take a Herculean effort given the form of Joe Moody and Karl Tu'inukuafe.

Ngani Laumape continues to have his admirers but it's hard to see him forcing his way past one of Sonny Bill Williams, Ryan Crotty, Jack Goodhue and Anton Lienert-Brown.

Nehe Milner-Skudder still has plenty to offer but he's going to have to deliver something compelling if he's to be picked as an outside back ahead of Ben Smith, Rieko Ioane, Waisake Naholo and Jordie Barrett.

Maybe the youngest Barrett is vulnerable but his versatility and goal-kicking will be difficult to overlook in a World Cup.

The three halfbacks and three hookers are unlikely to see a change in the pecking order because there is no one outside the group currently banging the door down to be in.

So that's it – a year out from the World Cup and only two questions remain unanswered - who will win the shootout between the emerging blindsides and whether to take Tuipulotu or Todd.