PADDY McCartin always thought he would return to the AFL one day. He just didn’t think it would be playing for Sydney, alongside his brother in the backline. When he thinks about it in those terms, he still can't believe it actually happened at Accor Stadium last weekend.

But it did happen.

After 1352 days, the 25-year-old made a fairytale return against Greater Western Sydney that almost everyone outside of the McCartin family didn't see coming.

McCartin showed glimpses of the prowess that inspired St Kilda to use the first pick in the 2014 NAB AFL Draft on him across 35 games. But his five seasons at the Saints were marred by eight concussions, each taking longer to recover from, each generating more external noise until it looked like he would never come back.

McCartin disappeared from view, searching far and wide for a solution. He spent a week inside the world-leading Neurologic Wellness Institute in Chicago in 2019 on the back of a recommendation made by former teammate Koby Stevens, who was forced to walk away from the game due to his own concussion issues.

He then worked intensively with a specialist in South Yarra four times a week for many months, retraining his brain and undertaking arduous eye exercises to get to a point where an AFL panel of concussion experts allowed him to resume his career last April.

Now McCartin is back, playing for the Swans like nothing happened. Although it did happen, and he hasn’t forgotten the journey that brought him back from the brink.

"I came up to Sydney, did the stuff in the VFL and did a program that the AFL and the Swans worked together on, working back into contact and contact training and working into a practice match that was on the first weekend of April last year. That was my first game so there was a lot of build up into it.

"When I was really going through 2019 I went to Chicago for the week, did the week of intensives there and then did four one-hour sessions a week with Brett Jarros who looked after me. It was a lot of work but ... that’s what I had to do to get back; not just back to footy but back to normal again."

There are two lasting images of McCartin during his time at St Kilda. Both involve sitting on a bench. One is next to then St Kilda head of football Simon Lethlean before he was placed on the inactive list.

The other is more poignant. McCartin is sitting on the bench at Mars Stadium in Ballarat with his hands on his head, following another head knock. Long-time club doctor Tim Barbour looks distressed. It looks all over.

"It took a long time (to get to this point). It was probably the best part of 18 months before I was back doing footy stuff without thinking at all about my head. Even then it was probably more like two years. This time last year I hadn’t played a game yet since my head knock," McCartin told AFL.com.au at the SCG on Wednesday.

But it wasn't all over. Despite his long history with concussion and the very real worry of chronic traumatic encephalopathy (CTE) hovering over the game, McCartin doesn’t play with any fears of another head knock, or what another concussion will mean for his life and his career.

"Funnily enough I don’t, and some people find that hard to believe," he says as we sit on the wing at the SCG ahead of Sydney's main training session on Wednesday night.

"It’s the same as any injury really; once you get past it and build up enough confidence (you don't worry about it). I did a lot of rehab and as you tick each goal off you put it behind you. Once I played that was it and I got through a few games and that was sweet. I feel pretty sweet now which is good."

Being cleared to play by a concussion panel was one thing. But being given the blessing to return to what he loves by those he loves was another thing altogether. Some will grimace when watching McCartin play football in the immediate term, given what he's been through. Some will question whether it’s the right thing to do, given how much and how little we really know about the long-term damage of concussion.

But despite the anguish football has brought their son, Matt and Jo McCartin – as well as brothers Tom and Charlie – were happy for Paddy to give it another crack once he was given the medical advice he wasn’t putting himself at greater risk than anyone else by returning to play again. The McCartin family, who are widely loved by many inside the Saints and the Swans, saw what life without football did to Paddy and just want him to be happy.

"I'm very, very lucky. I never take for granted my family and my partner Lucy as well. When I was going through all that too, they were unbelievable. I'm only as good as the support I have around me. Without any of them I wouldn’t have been able to get back," he said.

"They are always just supportive of whatever makes me happy. When I went through that stuff in 2019, they saw what footy being taken away did to my ability to be happy. I think when I made the decision after speaking to all the specialists with the AFL, when they said to me I could potentially get back, I think that gave me a real opportunity to put something in place and a lot of motivation. The same as me – as long as the specialists were happy and that I'd get back to normal – then they were pumped."

After a nightmare few years that were broadcast for the world to hear in that jarring Triple M interview in May 2019, McCartin packed up his life and moved to Sydney ahead of the 2021 VFL season. The Swans had shown some interest in providing him with an AFL lifeline if he could prove he could play again, but hadn’t promised him anything. The chance to escape the Melbourne football fishbowl and live with his brother Tom again was part of the lure of heading north.

"The opportunity to get out of Melbourne was really appealing to me and obviously Tom was up here. Pre last year I'd never really spent a whole heap of time with Tommy since we've both finished school. He moved straight up here when I was in Melbourne and we would see each other during the year but not a whole heap, so that was really appealing to me," he said.

"The Swans were fantastic and so supportive in what I wanted to do. They helped me tick a lot of the boxes with what I needed to do with the AFL before I came back and played as well. I was always really hoping that I would end up on the list here, or somewhere, but here would have been ideal."

McCartin was on track to earn a second chance via the mid-season draft last year when a moment of madness happened in May. The usually gentle giant struck former North Melbourne and Geelong forward Aaron Black behind play in the VFL, resulting in a five-game suspension from the Tribunal that almost ended the dream.

While it resulted in condemnation and more scrutiny, it ended up being a blessing in disguise in one way. When the Sydney went into lockdown again, McCartin travelled with Swans AFL program putting himself under the noses of John Longmire, Charlie Gardiner and the football department for a prolonged period. It ended up being an important factor in list manager Kinnear Beatson signing him during the pre-season supplemental selection period. They got to try before they bought in more ways than one.

"I definitely did (think it was all over). It was obviously a big error and something that I look back on not very proudly at all. But it's one of those things where hopefully people know my character and even Aaron hopefully he does too. Definitely at that point I thought I could be in a bit of strife here," he said.

"But I stuck to my guns and tried to do everything I could to get back on track. Luckily that hubs things came at the right time because if I hadn’t have left Sydney I would have been stuck in Sydney in lockdown and I wouldn’t have been able to play for the rest of the year and that might have been me done. There is little sliding doors moments I look back on and go I was pretty lucky."

Now Paddy is playing in the same defence as Tommy, who had only played seven games when McCartin played his final game for St Kilda in round 16, 2018, but is now 35 games ahead of him. How did someone who was rated the best 18-year-old in the country as a key forward and had never played down back before turn into a defender that looks like he's been playing down there all his life?

"It actually came about last year when I came up. I think the Swans crew thought it might be a good idea to play me behind the ball, so I've got everything in front of me to start with," he said.

"I think a lot of the issues I had with my concussions at the Saints is when I would run back like an idiot – which is stupid – and I would just get cleaned up. I think they just wanted to get me behind the ball and have everything in front of me and just get used to it.

"I played the first few rounds down there. I didn’t set the world on fire, but I think it was a needs basis really with the Swans. We just needed another tall down there and I was happy to do that in the pre-season, happy to play whatever role they needed. I picked it up OK. I'm still learning heaps, even on the weekend against the Giants there is so much stuff that I learnt. I really enjoy it."

McCartin may be back playing in the AFL again, but things are clearly different. He is no longer the heir to Nick Riewoldt's throne, the great white hope who was going to lead St Kilda back to the promised land. Perspective changes everything, especially in elite sport.

"It's chalk and cheese really. I think what I've been through has given me a different perspective on footy. A lot of people asked me if I got nervous last weekend and I didn’t really," he said.

"I haven’t been getting nervous at all before games, which I don’t know if its maturity or some of the stuff I've been going through before games gives me a different perspective. I think it is different and I really enjoyed my time at the Saints, but I'm really enjoying my time up here."

McCartin never gave up believing he would make it back. But that doesn’t mean he can believe it's actually happening. He had to wait the best part of four years to play again. Now he is planning to play for as long as he can, making up for lost time.