Sportal.co.nz 15.Sep.2013Getty Images
Carter injured the acromioclavicular (AC) joint when he was tackled by Bismark du Plessiss in the opening 16 minutes of Saturday night's 29-15 win over South Africa in Auckland.
The 31-year-old clutched his right shoulder immediately after making impact with the Eden Park turf and remained on his knees until team medics assisted him from the field.
"I'm not sure how long he's going to be out for but he's done an AC," said coach Steve Hansen.
"Usually they are for six weeks."
If Carter is indeed invalidated for more than four weeks, he will miss the All Blacks' trip to Argentina in a fortnight, as well as the rematch against South Africa in Johannesburg.
While Beauden Barrett could move up the pecking order, Aaron Cruden (knee) is expected to be fit and should take over the play-making duties.
Crusaders utility Tom Taylor (ribs) is also an option after making an impressive Test debut against the Wallabies in Wellington.
Meanwhile, Carter was seen with his arm in a sling following the match although there didn't appear to be any separation between the joint.
Scans could determine the injury to be a grade 'one' or 'two' meaning Carter would face a shorter recovery period and would be available for the third Bledisloe Cup Test against the Wallabies in Dunedin on October 19.
It was a huge blow for the All Blacks, who also lost Israel Dagg (hematoma) at half-time.
But Carter's injury would ultimately hamper the visitors' chances of ending their winless record at Eden Park which spans way back to 1937.
Although the incident appeared to be well-executed tackle, referee Romain Poite deemed it to be 'dangerous play' and ordered the Du Plessiss to spend 10 minutes in the sin bin.
He was later awarded a second yellow card to become the first Springbok sent off against the All Blacks since Andre Venter was marched for stomping on Sean Fitzpatrick in 1997.
It became the main talking point and marred what was supposed to be the biggest Test match of the year.
However, Hansen was quick to heap praise on Barrett and other rookies such as Sam Cane, who was tasked with replacing captain Richie McCaw in the No.7 jersey.
And while Cane answered his critics with a well-earned try in the second half, hooker Dane Coles can also be proud of the 40-odd minutes he contributed to the bonus point win.
"I think they're the things we should remember about the game," said Hansen.