Once trapped in an AFL nightmare, all of a sudden, Paddy McCartin is living the most unlikely of dreams.

For a couple of years, playing in an AFL final appeared an aspiration that had passed concussion-ravaged McCartin by.

The former No.1 draft pick was delisted by St Kilda at the end of 2019 after eight concussions limited him to 35 games in five seasons, without a finals appearance.

He sat out 2020 before returning to play VFL for the Swans in 2021’s COVID-19 affected season.

Then Sydney took a punt on McCartin as a pre-season supplementary selection in January, snapping him up as a key defender to play alongside younger brother Tom.

The older McCartin has thrived, playing all but one game and becoming a crucial interceptor.

Now he’ll take on the biggest stage of his career: Friday’s qualifying final against reigning premiers Melbourne at the MCG.

“There were a lot of points where I thought I’d never play a game again, let alone finish third and be playing in a finals series,” McCartin told AAP. 

“So I pinch myself at what’s happened this year, and I feel very lucky.

“Playing a final against Melbourne at the MCG, it’ll be pinch-yourself type of stuff. 

“But the real stuff starts now and we’re bloody looking forward to it.”

The 26-year-old is still “learning the ropes” in defence but has improved every game.

“They say it about every player – you get that continuity in your footy, you get confidence from that and you feel a bit better in yourself,” he said.

“So that’s generally the case for me. 

“I hadn’t played for a lot of years and I’ve felt that continuity as we’ve gone through.”

The learning curve even included “a little bit of a spray” from coach John Longmire in round 23, when McCartin temporarily forgot his playing duties and rushed to scuffle with Max King.

The St Kilda gun had put Tom down behind play.

“I was just being a protective big brother,” McCartin said with a laugh.

“I’ve got to stop being so protective. Tom’s a big boy, he’ll be fine.”

Most importantly, McCartin, who is in talks with Sydney about a contract extension, is back having fun.

“I enjoyed the pre-season, I enjoyed getting amongst the boys again, I enjoyed playing my first game, being with my brother. I’ve enjoyed all of it,” he said. 

“I haven’t taken any of it for granted and I feel really lucky.

“I’m loving my time at the Swans so hopefully I can keep that going for a few more years to come.”