In October 2008, Horsfield was diagnosed with testicular cancer, and advised that his playing career was over. As the disease was discovered in its early stages, no chemotherapy or radiotherapy was needed, surgery proved successful and less than two months later he was given the all-clear. Horsfield decided to make his illness public to help spread awareness of the disease, and lent his support to a Premier League-backed project launched in 2009 to promote men's health issues. He said: "Getting cancer was something I had to get over. I got it, wanted to beat it and I did. Now I am just glad that I've got another chance in football."