James Mortimer 23.Nov.2012Getty Images
Carter has been named at ten for the All Blacks, and initially Hansen said his absence from training was merely precautionary.
However the All Blacks coach said that a decision will be made over Carter in the next 24 hours.
If he is replaced, it is likely that Aaron Cruden will walk into the starting team for the second straight week, with Beauden Barrett under a minor cloud with rib troubles.
As the All Blacks trained at the University of Glamorgan in Pontypridd, Carter looked to be in discomfort after kicking the ball - although there was no repeat of his agonising fall when kicking a ball in training last year prior to facing Canada - an apparently simple act which ruled the Crusaders maestro out of last year's Rugby World Cup.
The potential for Carter to be ruled out could cause a complete change in the halves, with named starting halfback Aaron Smith being careful with his knee injury suffered against Italy in Rome, although it is not expected to rule out the Highlanders number nine.