The 24-year-old did not play a single match last season after having his appendix removed, and he also suffered two prolapsed discs in his lower back.
"I spoke to the specialist last week and he told me that's it. The injury's really interfering with my everyday life, I'm struggling to do normal things let alone start rehab," he told the club's official website.
"It's pretty bad at the moment, but I'm staying in close contact with the medical staff at Hull FC and hopefully over the next year or so I'll start to see some signs of improvement.
"I'm not sure whether I'll stay involved in the sport or look for something outside of rugby league yet but I'm a big believer in that as one door closes, another one opens."
Burnett made 55 Super League appearances during his short career.