The All Blacks lock was part of a group to enjoy some time off when the side travelled to face Argentina in Buenos Aires in September, then withdrew from selection for tests in South africa, Australia and the Northern-Hemisphere tour after he and wife Niki lost their baby boy prematurely.
Retallick spent the ensuing four months spending time with Niki and their 1-year-old daughter Sienna, before returning to the training paddock with the Chiefs this week.
"We're going good. It was a nice break, well, given the circumstances but it was good to rest the body," he said after training on Tuesday.
"Now we're here, the extra few weeks have caught up on me, running around yesterday in the 30-plus degree heat was a bit tough."
Retallick last played a competitve match of rugby on September 16 - in the All Blacks' 57-0 beat down of South Africa - and was eager to get back into the swing of things.
The Chiefs were set to be somewhat of a new-look team in 2018, with the likes of Aaron Cruden, Tawera Kerr-Barlow and James Lowe having departed the side at the end of their last campaign.
New head coach Colin Cooper has confirmed Damian McKenzie would start the season as the first-choice No 10, leaving the fullback jersey up for grabs, while the No 11 and No 14 jerseys were expected to be heavily contested.
The Chiefs begin their Super Rugby campaign against the defending champion Crusaders in Christchurch on February 24.
And while he and his family had been through a hard time over the past few months, Retallick said time away from the game hadn't altered his approach to playing rugby.
"It just same old for me. Rugby's a pretty simple game. I'll just focus on that, that's what I'm here to do so I'll be looking forward to getting back out there in round one."
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