James Mortimer 14.Aug.2012Getty Images
With the squad finalised for the tournament, only being called up as injury replacements will see any of the three feature.
The All Blacks are preparing to face the Wallabies in the opener of the new tournament, evolved from the Tri Nations, and the first match of a three-game series for the Bledisloe Cup.
Clarke, who had his knee injury assessed by All Blacks doctors, could potentially be an option with just three locks - Sam Whitelock, Brodie Retallick and Luke Romano - in camp.
Kerr-Barlow and Barret could effectively be considered the third ranked halfback and first five-eighth respectively, and both will play a role in the All Blacks training, featuring yesterday and today.
Both players, who the All Blacks coaches feel could take the step up to test rugby, could feature in the end of year tour.
Aaron Smith and Piri Weepu are the halfbacks for The Rugby Championship, while Dan Carter and Aaron Cruden are the number tens.
Barrett scored a Hurricanes franchise record 197 points this season, while Kerr-Barlow finished the Investec Super Rugby season as arguably the form nine of the competition.
Clarke, along with Liam Messam, led the Chiefs to their maiden Investec Super Rugby title, the second major trophy the big lock has got his hands on recently, guiding Taranaki to Ranfurly Shield glory last season.