Millar suffered a torn ligament in the early rounds of the Bunnings NPC that caused a few setbacks more than usual.
"A specialist found my tibia and the bottom of my leg were rubbing which was stopping a few things from healing properly."
Adding to his frustration was suffering a similar injury in Super Rugby Pacific and then coming back and getting into a position with the prospect of a lot of minutes, only to have the injury occur in his second game.
He's training three days out of five in the pre-season build-up and is happy with his progress, considering there is plenty of time before Super Rugby Pacific starts.
"I've gradually been working it back, but it's now where I can do most activities.
"It was good having older boys around, especially during rehab, giving me a few tips to keep my mind focused.
"There's quite a good vibe in the team. It's different from previous pre-seasons in how we run it; everyone is upbeat now.
"The new coaches, especially Kenny [Kendrick] Lynn, have changed a few of our philosophies around attack and we have got some new strength and conditioning coaches, so we are training, with less time on the bikes and rowers, and doing more hard work on the field."
Millar has come through a remarkable era of development from his home region centred on Gore, primarily through Gore High School's rugby programme. The region has already produced an All Black in prop Ethan de Groot, a year or two ahead of Millar. Others who have emerged are his Highlanders teammates Finn Hurley, Jack Taylor, Hayden Michaels and Harrison Morton.
Millar said he wasn't quite sure why things had happened their way, but the group were good mates who spent lunchtimes at school and weekends together, and he felt that friendship resulted in them pushing each other to the level they had reached.
"We're all close, went to the same schools growing up, and have spent a lot of time together through the age grades."
Millar finished his schooling as part of the Otago Boys' High School development programme, which he said exposed him to a better level of rugby and challenged him to improve.
"It really pushed me out of my comfort zone going up to Dunedin."
Since joining the Highlanders development group, he has found mixing with top players to be another driver.
"It's been awesome and I feel like every first-five I've played with coming up through the grades has been more than willing to help."
He said it also helped that, like every other boy in New Zealand, he had a player like All Blacks great Dan Carter to look up to as a blueprint for playing in the position.
"It motivates you to want to try and get anywhere near his level."
After his injury frustrations, motivation is not a problem as he seeks to become the wearer of the No.10 jersey for the side or to get as many minutes as he can on the field.
Having nearly five months out due to the ankle injury meant he couldn't build on the hard work he had been putting in to develop his speed.
"At the moment, I'm trying to work up to that top speed, and hopefully, in a couple of weeks we can start up with that programme and try and get a bit quicker."
Millar has been working with one of his conditioning coaches on the mechanics of his running and said it was hard to get used to and quite challenging with some of the changes required, but with an end goal in mind, it was worth it to stay in the process.
