Why NZ need three flyhalves

All Black playmaker Dan Carter has recovered enough from his injury to travel, but New Zealand coach Steve Hansen has included some additional insurance in the team.

Carter is expected to be fit for the team's remaining Rugby Championship matches - away against Argentina and South Africa, Hansen said after naming a 28-man squad for the trip.

Although Carter has been cleared to travel, a third flyhalf, Beauden Barrett, has been added to the touring party as a precaution, with prop Wyatt Crockett losing out on a place.

"Dan is recovering well from his calf injury and we are expecting him to be fit for selection for the Argentinian Test," Hansen said.

"However, to be on the safe side we are also taking Beauden Barrett as cover at No.10, alongside Aaron Cruden.

"As we are only able to take 28 players on tour, to include Beauden we unfortunately have to leave one player behind and the logical choice was for a prop to miss out.

"In this case, it made sense to leave Wyatt Crockett at home as we can cover all our bases with the other four props," Hansen added.

The All Blacks are unbeaten in the championship after four matches and will wrap up the title with a game to spare if they beat Argentina in Buenos Aires on September 29.

Their final match, against South Africa, is in Soweto on October 6.

Carter, the world's most prolific points scorer, missed the last two matches because of a calf strain but has been doing light training in the past week as well as pilates and weights sessions.