Kennedy was sidelined for three months with two slipped discs in his back, which followed a similiar injury struggle at Pittodrie.
The 30-year-old said: "It bothered me before when I was at Aberdeen. I had two stress fractures in my back and a slipped disc.
"With your back you just think it's a spasm. You don't really think it'll be serious, so they tried to push me through it for a couple of months and that did more damage to it.
"They realised and then I was out for over a year. I got back, played for a year and came here. I'm not sure what happened this time but it ...