Beauden Barrett could be in doubt for Argentina test

Beauden Barrett is in doubt for this weekend's All Blacks Rugby Championship test against the Pumas in Christchurch after sustaining a knock at training on Tuesday.

Barrett was said to have suffered a "knock" as the team trained at Rugby Park, the home of Canterbury and the Crusaders, on Tuesday morning.

No diagnosis was available to the media because he hadn't been assessed by the team doctor.

Three weeks ago Barrett suffered a nasty fall onto his neck after attempting to catch a high ball against the Springboks in Mbombela.

Barrett came off the bench the following week in the All Blacks victory at Ellis Park, with Richie Mo'unga promoted to start and playing an influential role.

If Barrett is ruled out this week Mo'unga will retain the starting role and Taranaki and Blues playmaker Stephen Perofeta could be in line for his test debut off the bench.

After training today, All Blacks fullback Jordie Barrett noted his brother's knock.

"I was down doing skills before and I saw he went off but I'm not sure what it was for I haven't seen him he's gone back to the hotel."