The two-time World Cup winner, who had not been selected in the matchday squad, left the team on the day of the first Rugby Championship match against Australia in Sydney last month to deal with a personal issue.
Liam Squire played the first two games of the Rugby Championship against Australia, while Vaea Fifita made his first start against Argentina last Saturday in New Plymouth. Kaino has played one provincial match for Auckland since he left the team.
"He came in yesterday. We've had ongoing conversations with him and it's a matter of bringing him back in," All Blacks assistant coach Ian Foster told reporters about Kaino's appearance at training in Auckland.
"He has had one (provincial) game, and we're keen for him to have another.
"He has been out of the game for a little while and he's got to show us he is in the right sort of condition to come back.
"But it's great having him back."
The 34-year-old, a virtual constant first-choice selection when available for the All Blacks since 2008, could face a battle to reclaim his test spot after Squire and Fifita have stamped their own marks on the team.
Squire has a more hard-edged element to his game similar to Kaino, while Fifita impressed with a stunning performance in New Plymouth where he scored an try from more than 35-metres out as he outpaced the Pumas' backline.
Lock Sam Whitelock, however, said Kaino's presence with the team back in Auckland had been a welcome one given the 81-test veteran's experience.
"He brings that harder edge to the environment," Whitelock said. "Whether it be walking through lineouts, or doing the physical stuff, it's good to have that older, experienced guy that demands we compete."
Fifita sat out training on Tuesday with a sore shoulder, but pundits in the rugby-mad country have said they expect the more experienced Squire to be recalled against a physical Springboks pack at North Harbour Stadium.
Foster, however, was not giving anything away ahead of the team announcement on Thursday.
"They were both pretty special in what they did," he said.
"They're both learning still, and there are areas in both their games where they've still go to get some greater clarity on the roles we need them to do.
"But it was great seeing them both go out on the park and express themselves with their athleticism."
(Reporting by Greg Stutchbury; Editing by Amlan Chakraborty)
