The 2005 Sydney premiership player made the call on Thursday, stating that further head knocks could have an impact on his life after football.
“I copped a little head knock and given my history over my career of receiving quite a few head knocks I’ve decided that it’s a risk that’s too great for me, especially now that I’ve got a young family, it’s more than just worrying about myself it’s what it means to my wife and my young daughter,” Dempster told saints.com.au on Thursday.
“For the last couple of weeks the club has given me some time to myself and some time to go and get some independent testing done, which I’m still going through at the moment and is an ongoing assessment. The testing had nothing to do with my want to retire; I know it’s the best thing to do for me and my family.”
Dempster confirmed there is no ill-feelings between himself and the club, after media reported the situation and said the 33-year-old was upset with the Saints for leaving him out of the round one side.
“It wasn’t what’s been reported in the media that I was upset with the club about not being picked for Round 1 and that there was all this angst and hate between me and the club,” Dempster said.
“I’m quite a quiet person so for it to be played out in the media was a bit hard for me to deal with. I’ve been lucky enough to go through 13 or 14 years as pretty much an unknown player, which I’ve been pretty happy with.
“For my character to be questioned a bit was upsetting for me, it was a little bit hard to deal with. I felt like I had to get on the front foot and address the situation earlier than I planned.
“It was purely a decision for me and my family and it’s the way I’ve decided to go and I’m pretty comfortable with my decision.”
Throughout his nine-year career at the Saints, Dempster played in back-to-back grand finals in 2009 and 2010, and was named to the All-Australian side in 2012.
“I’ll be forever grateful for St Kilda. I spent the first few years of my career at the Swans as very much a fringe player,” he said.
“The opportunity St Kilda has given me to grow as a footballer has been enormous. I don’t think my career would have been half as long if it wasn’t for my move down here.
“Football has been my something great and the club has given me the opportunity over ten years to contribute to something great. I’ll be forever grateful, I’ve met some wonderful people, had some wonderful opportunities.
“We’ve played in a few grand finals, unfortunately we didn’t get the results we were after but the friendships and bonds you build over those periods you’re quite successful and you play a lot of football together is something I’ll cherish forever.”