ST KILDA key forward Paddy McCartin has detailed the extent of his lingering concussion symptoms and the grave concern for his wellbeing in a remarkably raw interview.

The No.1 pick in the 2014 draft sustained the eighth concussion in his AFL career in a JLT Community Series match against the Western Bulldogs in March.

McCartin still struggles to perform day-to-day activities such as going to the supermarket or a café and driving a car, and is unable to physically exert himself beyond being on an exercise bike.

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Brain scans in the immediate weeks afterwards revealed "abnormalities" that specialists were confident would dissipate in time.

The 23-year-old said he hadn't seriously considered retirement, especially while he continued to feel unwell – advice concussion-sufferer and former AFL footballer Koby Stevens gave him.

"It's very concerning for me and I think for my girlfriend and my family, because I'm sort of just a shell of a person that I was," he told Triple M.

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"I'm just completely different, and it's gone from one day when I was playing to within 10 seconds being different."

McCartin continues to deal with extreme headaches that make it difficult for him to sleep and he constantly woke up in "pools of sweat" in the first six weeks of his recovery, which is ongoing.

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He is on medication designed to help him sleep and he also received a cortisone injection to the back of his head that wreaked havoc with the Type 1 diabetic's blood sugars for "a week or so".

The Saints have ruled McCartin out of playing this season and placed him on the inactive list, meaning they can select a replacement player in Monday's NAB AFL Mid-Season Rookie Draft.

"It's been a tough few months. I haven't really done a whole heap – I haven't been doing a lot of anything, really – and that's probably been the hardest part," McCartin said.

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"I've sort of lost my footy identity a little bit, but then also my identity as a person as well, just because I can't do stuff…

"The hard thing is there's no real timeframe on it. So, hopefully, I'm better next week, but I could be better in a year or six months – I don't know – so it's been tough."

McCartin, who is completing daily brain-related exercises, remains sensitive to light and sound and said the symptoms had lasted longer than any of his previous head injuries.

That sensitivity has also meant he is unable to spend longer than a couple of hours at a time at his football club and has overall robbed him of "a purpose".

"I've spoken to a lot of specialists and a lot of doctors and I think firstly with how many concussions I've had, they're all different," McCartin said.

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"So you don't relate just the number of concussions you've had … but definitely with how I'm feeling, it's been three months and that's a long time to feel how I've felt.

"You've definitely got to weigh everything up (but there is) no timeframe on things."

St Kilda football boss Simon Lethlean indicated McCartin was still targeting an eventual return to playing.

"Paddy's symptoms are slowly improving but while they still linger, we are unable to put a timeframe on his return," Lethlean told saints.com.au.

"Given he isn't able to train at a high intensity at present; being able to complete the necessary training to return to playing matches before the end of the season now appears unlikely.

"Our focus first and foremost is on Paddy's health and wellbeing and ensuring that he becomes symptom-free.

"Once that occurs, we will be in a position to put a more accurate timeframe on his return to training this year and his program and plans for the (upcoming) pre-season."

McCartin has lined up in just 35 matches throughout his career.

The 2019 NAB AFL Mid-Season Rookie Draft will be broadcast LIVE on AFL.com.au, the AFL Live Official App and Fox Footy from 6:30pm AEST on Monday, May 27