Thornton, who has spent much of this season returning from a persistent groin injury, suffered a broken leg playing for South Fremantle on June 7 and faced a further 8-10 weeks on the sidelines.
He said the thought of putting his body through yet another rehabilitation program was a major factor in his decision to retire.
“Rehab can be a bit draining,” he said. “It can take you to your limits every day. I’ve been thinking about retiring for a while now. I’ve only played two-and-a-half WAFL games this year. I just couldn’t put my body through another AFL pre-season.”
Thornton, who in 2003 was diagnosed with Crohn’s disease - an inflammatory bowel illness - said he hoped he had been a good role-model for others who might have had similar problems.
“As I've gotten older and more mature, I’ve realised how I could inspire other people,” he said.
“Hopefully, they have had a look at what I’ve done and said to themselves, ‘I can get myself right and I can make myself healthy’.”
Senior coach Mark Harvey said Thornton’s battles over the years with injury and Crohn’s disease were an inspiration to everyone at the club.
“He achieved highly in an elite field, knowing that not a lot of things went right for him, from illness to injury,” Harvey said.
“He never gave up the fight, until now.”
