All Blacks' selection not locked in

New Zealand are sweating over the fitness of one of their key players, just days out from their Rugby Championship showdown with Argentina, in Buenos Aires on Saturday.

All Black coach Steve Hansen said he was giving Sam Whitelock every chance possible to prove his fitness.

The All Black lock is recovering from a rib injury and his inclusion in this weekend's Test against the Pumas is in doubt.

Hansen told the media that Whitelock is key to his gameplan.

Hansen said the last time they played Argentina they used three specialist locks and they want to have that happen again.

Meanwhile Aaron Cruden's booze binge has given a hefty leg-up to Beauden Barrett in the tight battle for the All Blacks No.10 jersey.

The 25-year-old All Black, Chiefs and Manawatu pivot was withdrawn from the tour of Argentina and South Africa after a late-night drinking session in Auckland at the weekend resulted in him missing the team's Sunday flight to South America.

"Potentially it's a great opportunity for me," Barrett told Fairfax Media.

"I'll just prepare as I normally do. It's another challenge, Argentina at home.

"I'll find out if I'm next in line when the team is named. We've just got to move on as a team. There's a big challenge."

Source: Newstalk ZB