Both men remain determined to make it to the 2015 World Cup but are fearful they will physically and/or mentally implode without an extended break or, in the case of Carter, time in a different environment.
All Black coach Steve Hansen is known to be in favour of both Smith and Carter, and a few other senior players, being able to take time out if they feel it will refresh and invigorate them to come back and have a crack at defending the World Cup.
There is a wave of young talent emerging in a number of positions but Hansen is convinced many of the core group who delivered the World Cup last year can still be world class and genuine first-choice All Blacks by 2015. He's prepared to allow them considerable leeway to prove that and his only caveat is that he doesn't want too many players on sabbatical at the same time.
Of the various 30-somethings in the squad, Smith is the most certain of his plans. He recently extended his contract through to 2014 and is understood to have negotiated a strategy to manage his workload. He will play for the Hurricanes in next year's Super Rugby, be available for the June tests and Rugby Championship but will not take part in the third Bledisloe test or three-match end of year tour.
Instead, he'll most likely rest, travel and recondition before returning to play in the 2014 Super Rugby competition.
Smith made his All Black debut in 2004 and has matured into arguably the world's best centre. But his body has taken a pounding. The midfield has become one of the most physical battlegrounds in the game and Smith has earned a reputation for his defensive clout.
It's easily forgotten that Smith was barely 85kg when he was discovered playing for Wellington in 2003. In the space of a year, he'd added 10kg and is currently around 100kg. But the toll has been considerable - his body isn't naturally designed to operate in its current dimensions and having recently turned 31, he knows he can't take his longevity for granted.
Carter's situation is a little different. He signed a four-year contract before the World Cup with the option of another sabbatical in it. He was the first player to be granted dispensation to play abroad as part of his contractual agreement with the New Zealand Rugby Union. He went to Perpignan in 2009 but managed only four games before he seriously damaged an Achilles tendon.
He retained a sense of unfinished business from his French sojourn but he too is close to turning 31 and the dangers of returning to the highly physical French league in 2014 would be considerable.
The indications at this stage are that Carter will most likely be available for all of next year's All Black programme but then possibly play in Japan from December 2013 through to February 2014 and not return to Super Rugby until after the June test window.
The Japanese league is not known for its physicality, and its shortness would provide Carter a nice overall mix in a six-month sabbatical - a change of scene where he would be well paid and able to focus on aerobic improvements and then a period of prolonged rest.
The other option would be for Carter to follow Richie McCaw's example and simply take a break from all rugby in the first six months of 2014.
Whatever he decides, it would seem the one thing not likely to happen is him being available for all Super Rugby commitments between now and the World Cup.
The All Blacks are not fretting about McCaw's absence next year, as it will provide Sam Cane with a chance to develop at openside and for Kieran Read
to mature as a leader. And should Carter be unavailable, the door will open for Aaron Cruden and Beauden Barrett.
The All Blacks will welcome the chance to develop their back-up options knowing, as they do, how easy it is to lose first-fives at World Cups.
- Gregor Paul, Herald on Sunday
