The 89-Test lock is expected to be a handy addition to Dave Rennie's team  to face Australia at their Eden Park fortress in Saturday's Bledisloe Cup opener.
The 32-year-old Crusaders talent, who only returned a fortnight ago in provincial rugby for Taranaki, opted to take a non-playing sabbatical last year and properly recover from ankle and Achilles surgery.
A bulged disc in his back required more surgery though and kept him out for another six months, meaning Barrett missed the entire Super Rugby Pacific season and the All Blacks' 3-1 series loss to South Africa.
Skipper under Scott Robertson, he returns under a new coach who described him as a "reluctant captain", with Rennie naming hooker Codie Taylor to lead after Ardie Savea's season-ending shoulder injury.
"I don't know what 'reluctant captain' means, to be honest," a relaxed Barrett said of Rennie's remarks.
He said he had spoken to Rennie several times before Savea was officially handed the captaincy.
"Whether he had that in his mind, to go in a different direction with the captaincy, that conversation may have confirmed that," he said.
"I'm hugely excited to be back in this team and looking forward to contributing in whatever capacity.
"There's been a lot of water that's gone under the bridge since I was last here. I'm excited to see where this team has shifted to."
Barrett said he was naturally drawn to the set piece battle against the Springboks, who dominated that facet of the game to clinch the series before losing to Australia in Perth.
The All Blacks have won their past 11 Tests against Australia, held the Bledisloe Cup since 2003 and boast a 53-Test unbeaten streak at Eden Park.
Australia haven't won at the venue since 1986.
"We're fully on alert for what's coming," Barrett, who was playing under-9s the last time the Wallabies won the Bledisloe Cup, said.
"We've already addressed a few things on where we need to get better, around the scrum.
"We'll see it on the grass, see those shifts and turn them into habits."
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