The 48-year-old retired in 2005 after an illustrious career, scoring 168 goals for the Italian club and 56 times for his country.
But he told Fifa.com he has "difficulty walking" because of the effort he put into his game.
"I gave much more than I actually had to give," Batistuta said.
In 2014, Batistuta revealed he had asked doctors to amputate his legs because of the severe pain he was suffering.
After surgery to relieve the pressure on his cartilage and tendons, his condition improved, but he has been left with mobility problems.
Former Argentina and Fiorentina striker Gabriel Batistuta has revealed he struggles to walk after his 17 years in football.