Clarke informed his teammates of his decision this morning, having failed to overcome the effects of a head knock he suffered during a pre-season training session.

The 22-year-old fell heavily as a result of a pack mark contest on January 18, with a final visit to specialists in Melbourne last week confirming his decision.

Clarke hailed from the small town of Booleroo Centre in SA’s southern Flinders Ranges. He played briefly for the North Adelaide reserves but returned to his family farm to ply his trade with “BMW” (Booleroo Centre/Melrose/Wilmington) in the Northern Areas Football Association – citing a love of the land and country footy – before being claimed by the Lions with the No.4 pick in the 2011 AFL Draft.

He made his debut in 2013 and played 56 AFL games for the Lions, who have vowed to continue providing support in his post-football life.

“It’s been a long process to get to this decision,” Clarke said in a statement.

“I’ve sought advice from multiple specialists who have all confirmed that the decision to stop playing football is the right one.”

Lions football manager Matt Francis said” “This has obviously been a very difficult decision for Justin, however our duty of care to him is paramount and we agree this is the best decision moving forward.”

“Justin has very definite plans for his career post-footy and that has had a big influence on his decision, and we fully respect that,” he said.

-AAP