That means the flying winger will miss the Highlanders season.
It is a bitter blow for the 23-year-old.
He was in magic form at Super Rugby level and was poised for another strong NPC season.
But his knee buckled underneath him about 15 minutes into the campaign opener against Southland at Forsyth Barr Stadium on Saturday.
He had to be helped from the field, and scans revealed the worst.
It is his first major injury and he told the Otago Daily Times yesterday he was still adjusting to the news.
The first priority is to get the swelling down and he will see a surgeon in Christchurch on Monday. He is hopeful he will get surgery next month, after which he faces a long rehabilitation.
"I’m taking it day by day at the moment." Nareki said when asked how he was feeling about it all.
"I think Sam Gilbert had the same injury and Folau Fakatava is going through it at the moment. Sam has done the rehab and all I can do is the same, really."
It is a little unsettling how easily the injury happened. He was running the ball back at the defence and tried to step off his right foot when his knee gave way.
"All of a sudden, I just felt this looseness in my knee and it just went."
The most time Nareki has spend on the sideline in the past has been about two weeks.
"This is my first major injury. Every athlete has one. But I’ve got great support at the moment so I’ve just got to chip away at it."
He was hobbling about on crutches but had them whipped away so he can build up the strength in his upper leg in preparation for surgery.
"It was quite good when I had the brace on because I got some sympathy.
"Now it looks like I’m definitely milking it."
Nareki is unlikely to be spotted on a rugby field before May. He had been touted as a potential All Black by some pundits, although he has not heard from the national selectors.
"I am gutted but there is nothing I can do about it. I’m just trying to focus on the positives.
"I’ll get to spend more time at home with the wee man."
That wee man is his 1-year old son, Jona jun, or JJ for short.
Nareki, who grew up in Whanganui, is closing in on 50 games for Otago and is really looking forward to reaching the milestone.
Everyone else was looking forward to him adding to his 25 tries for the province.
