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

The nature of Barrett's injury is unclear at this stage but the All Blacks playmaker left training at Rugby Park, the Crusaders base, early to return to the team hotel for assessment.

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 Taranaki and Blues playmaker Stephen Perofeta could be in line for his test debut off the bench.