"This is the hardest four months of my career and I'm just happy to be back in the routine of being a footy player again.
"I got into some dark places, I couldn't really do any exercise and I had conversations with my partner about retirement. It was really hard.
"It was constantly on my mind. It wasn't until I saw a sports psychologist at the concussion clinic I got referred to that I got some structure in my life.
"I was quite negative, not in a bad way, but I thought this might be it.
"You just become so conscious of your brain and the way you think ... you just watch the lads go about their work, but even going to the stadium, I would struggle with the noise and be down for a couple of days.
"But I slowly clawed my way back."
Now he will just need to switch up mentally to rip into his work in Canberra, after four months where he admitted he was a terrible rugby-watcher.
"There's obviously a bit of fear, that's usual. Knowing the way I play and my attitude, once I'm in the thick of it, I'll be just thinking about playing footy.
"I've trained with the Canes boys for a couple of weeks and I've been getting into them at training. I've just built up my contact, and getting that belief and confidence back, and I'm in a good spot."
Hurricanes coach Chris Boyd says Coles will probably assume the captaincy, whenever he enters the fray.
"It's been a journey for him, a bit frustrating, and he's had his ups and downs, but there seems to be a point where a smile comes back and the spring is back in the step," Boyd says.
"He doesn't like to lose at anything. He's a massive competitor, and incredibly committed to the Hurricanes and the cause."
On the debit side, Vince Aso's groin is still not right and he is not travelling to Australia, but may be right for the semifinal.