The Norwood prospect, who was named an All Australian after an impressive under-18 championships earlier this year, underwent a routine electrocardiogram in the lead-up to last month's Draft Combine.
The test showed unusual results and although his doctor wasn't sure of the issue, he advised Villis against doing any testing at the combine.
After the combine he met with a cardiologist in Adelaide, who observed the sets of results and said he was 90 per cent sure Villis had a form of hypertrophic cardiomyopathy, which can thicken the muscular wall of a person's heart and make it more difficult to pump blood.
"It didn't really mean much to me because I didn't know what that was. I asked all the questions and he said if I have that condition then I'll probably never be able to play competitive sport again to a high level because it gets my heart rate too high," Villis said.
"When I first found out I was pretty devastated because footy was everything, but when you think about it, it is your life.
"I'm not going to give up without knowing for 100 per cent what I can and can't do. I want to see everyone I can and know everything I can so I know whether I can play footy and how I need to live the rest of my life.
"It's frustrating at this stage but I want to get more opinions over in Melbourne before I give up on it."