McCartin has not played a regular season game this year after he was concussed in a pre-season match against the Western Bulldogs in Ballarat.

Fresh doubts hang over his career after he was placed on the long-term injury list on Sunday.

The 23-year-old, who wears a protective helmet, is believed to have been concussed eight times since 2014 and is still struggling to shake off symptoms from the head knock he sustained in March.

He spoke to Triple M about the debilitating aftermath of the knock that occurred when he backed into a marking contest.

''(I'm) not great to be honest, it's been a tough few months," McCartin said.

"I haven't done a lot of anything, really, and that's been the hardest part.

"I've lost my footy identity a little bit but also my identity as a person as well just because I can't do stuff.

"I can't go to a supermarket when it's busy or a cafe with my girlfriend or drive my car.

"The hard thing is that there's no real time frame on it.

"Hopefully I'm better next week but I could be better in a year or six months. I don't know."

McCartin is suffering from light and sound sensitivity, wakes up in pools of sweat and has headaches that require drugs to help him sleep.

He has better days as his recovery drags on, but his worst days are just as bad as they have ever been.

Despite all of that he isn't considering retirement, but neither is he thinking about getting back on the field.

"I haven't thought about that much but playing is going to be a by-product of me feeling better again,'' he said

McCartin's horror run with concussion and injury has limited him to just 35 senior appearances since he was the No.1 pick at the 2014 draft.

His move to the long-term injury list will allow the Saints to participate in Monday's mid-season draft.

"Paddy's symptoms are slowly improving but while they still linger, we are unable to put a time frame on his return," Saints football chief Simon Lethlean said in a statement released on Sunday.

"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 well-being and ensuring that he becomes symptom-free."

Australian Associated Press