FOR JUSTIN Clarke, the decision on when – or if – to return to the football field is a tougher one than for most.
The young Brisbane Lions defender was ruled out indefinitely on Tuesday after failing to overcome a concussion suffered at training on January 18.
But Clarke is not your typical AFL player.
For most, making a list and forging a career is the be-all and end-all, but not for this 22-year-old.
Clarke is one of the smartest men in the AFL, scoring 99.95 per cent on his Australian Tertiary Admission Rank entrance score.
He is studying engineering, tutors high school physics students, helps Lions' players and staff with their own studies, and if he was 2cm shorter, would likely be an Air Force pilot (yes, he has a license, but is too tall).
Clarke's career after football should be both fulfilling and prosperous.
He is yet to pass the first concussion test after copping an accidental knee in a marking contest a month ago.
The country South Australian suffers mild headaches, is tired all the time and can't concentrate for any length of time.
His one attempt at exercise – riding a stationary bike – wiped him out.
It's a condition former teammate Matt Maguire knows all too well - he was forced to retire less than 12 months ago after failing to overcome concussion.
"I wasn't able to run or train with any intensity," Maguire told AFL.com.au.
"As soon as I got my heart rate up, I got dizzy and needed to go home and go to sleep.
"I'd do a few run throughs and have to go home to rest for four hours."
Maguire retired two months after suffering his concussion.
But just like Lions legend Jonathan Brown, who retired in 2014 after one final knockout blow against Greater Western Sydney, Maguire had already served a distinguished career and was at ease with his decision.
Clarke has played 56 games in four years and is just a pup in his career. After being selected as a rookie in late 2011, the 195cm defender has done an admirable job in a defence often under fire.
Maguire echoed the thoughts of others around the Lions, saying Clarke would consider his post-football life above anything else.
"I'm not worried if I lost a couple of brain cells, but I think that'd be more relevant to Jase (Clarke)," Maguire said.
"Jase has got a really bright academic future in front of him that requires a high level of intellectual application, and that's something I'm sure he'll consider during what I hope is a speedy recovery.
"I reckon if he had to choose between the two, just my read and I could be wrong, he'd say: 'I don't want to risk my head'."
Maguire has not exercised since retirement and said any more than one or two alcoholic drinks was also now off limits.
The Lions' medical team is consulting with leading concussion expert Dr Michael Makdissi in Melbourne, who will assess a further round of Clarke's scans next week.
"You play footy for 15 years if you're lucky," Maguire said.
"It could be a sixth of your life at most. But this is the rest of your life we're talking about."
We're behind ya Clarkey. You'll b back in no time. #restupmate.— Lewy Taylor (@LewyTaylor7) February 16, 2016