The prolific forward suffers from a condition that causes weakness and weight loss.
Former Down forward Marty Clarke has been forced to retire due to an ongoing medical problem.
Clarke, who played an instrumental role in Down's journey to the 2010 All-Ireland final, was diagnosed with Addison’s disease three years ago.
The condition affects one in every 100,000 people and causes the patient to experience abdominal pain, weakness, and weight loss.
Clarke decided to retire upon advice from medical experts. The 29-year-old revealed the news in an exclusive interview with the Irish News, and explained that it was a difficult decision for him to make.
"I made the decision because of the stress it's putting me under. The dynamic nature of Gaelic where you're running, you’re jumping, I was putting my body under a lot of stress."
"I just felt completely zapped from the start of the game to the finish. When I got home it was taking me longer and longer to recover."
Marty Clarke retiring at 29. Sad that we didn't get to see more of him. At his best, he was special.— Kieran Cunningham (@KCsixtyseven) March 2, 2017
"I went and got a bit of advice from the consultant and he recommended I stop competitive sport. It probably hasn't sunk in totally but I know in my heart, the way I was feeling after a lot of football games for club and Queens, that it's not safe and I'm not doing myself justice probably."
"The Kingdom (his club An Riocht) have been first class and it was pretty emotional telling the fellas."
Clarke previously played for Aussie Rules club Collingwood, winning 73 caps for the side between 2007 and 2009.
He also collected an All-Star in the year of their All-Ireland appearance before returning to Collingwood where he was diagnosed with the disease. He came home again in 2014 but didn't line out for Down again.