"I just didn't feel right heading up to Auckland [to join the All Blacks camp] and I was having headaches all day. I couldn't sit in meetings - the concentration levels needed - after taking a big knock."
LISTEN: Sam Cane: Charlie Ngatai and personal struggles with concussion
It could have been Ngatai's year. The departures of both Conrad Smith and Ma'a Nonu to France and the fact Sonny Bill Williams committed to the Olympic sevens programme meant a vacancy existed in midfield. He was on course to snare the All Blacks No12 jersey after being one of the best players in the early rounds of Super Rugby for the Chiefs.
"I saw the players leaving [the All Blacks] and I was playing good rugby through Super and then I got a knock. It was frustrating. I wanted to be in the All Blacks, especially after being named."
Ngatai's symptoms included dizziness, light-headedness and headaches and he found he needed to rest and sit down for up to 15 minutes after training to clear any light-headedness.
He's much better now but is yet to test his recovery in contact and it was announced this week he would take the rest of the season off, meaning he will miss the remainder of the Mitre 10 Cup for Taranaki and any chance of making the All Blacks' end-of-year tour.
"All [the medical staff] say I'm going to have a full recovery after the way I have progressed in the last four or five months. It's quite good, really. But it's a matter of time and it's really up to me when I'm feeling right to push it to that next level and that next level is contact, because everyone has to make tackles and go into contact at some stage, and maximum heart rate training.
"I thought about giving it a little nudge and trying to play again but I didn't think I was ready. It's going to take longer to get confident and go into those places."
The greater understanding of concussion has made those decisions easier but it's also increased fears. American football in 2013 paid out US$765 million ($1.05 billion) to more than 4500 former players, some suffering from depression, dementia and Alzheimer's amid accusations the NFL concealed the dangers of concussion.
A similar scenario is emerging in New Zealand with a number of former players admitting they are struggling with similar symptoms and their possible link to rugby. Others, like Ben Afeaki who retired at 27 because of concussion, are concluding their health has to come first.
Ngatai's Chiefs team-mate, Sam Cane, was concussed twice earlier this year. He passed a sideline test during the Super Rugby semifinal against the Hurricanes and played on but spent the next three days with headaches and nausea.
"It was worrying me when I was feeling crook and you don't know when you are going to get better," he said. "I really feel for people who have to experience that for a decent period.
"I try not to worry too much about the future. Time will tell."
Ngatai had a simple message for anyone who suspected they might be concussed.
"If you take a knock, stay down and tell the doc or your team-mates about it because if you take another one, you are risking your life."
