A hamstring injury and then a fractured wrist have limited the 29-year-old to two games this year – against Richmond in round two and the Sydney Swans on Anzac Day – but he is feeling refreshed ahead of Friday night's clash against Collingwood.
With Magpies spearhead Travis Cloke looming, Dempster shapes as a key player at Etihad Stadium with his ability to play tall and small and act as the glue in an undersized back six.
He said the Saints had done their research on Cloke this week and would work together to help forward-turned-backman Rhys Stanley, who is considered his likely opponent.
"We went over a few stats of his and we know that the ball does go through him quite a lot inside 50," Dempster told AFL.com.au.
"He's such a big powerful guy, he's got a massive engine and when he's really on he's kicking big bags of goals.
"If someone is going to be dropping off then they're going to be looking at Travis Cloke to get in his way and try and give Rhys a bit of support.
"If we can help Rhys out in the air and give him some support then we'll do that."
The move of 200cm Stanley into defence is seen as critical for the Saints to contain the AFL's big forwards this year, but Dempster's return to full fitness is also significant.
A lockdown option on small forwards, his ability to peel off and help teammates in the air will also be welcomed by Sam Fisher, James Gwilt and Jason Blake.
"Talking with Scott (Watters), my role is going to be similar to last year," Dempster said.
"At times I'm going to have to play on a dangerous small and then there will be times where I can be a plus-one behind the footy and try and give the backline a bit of drive.
"At different times I'm going to have to play small and tall."
Team success came early for Dempster, who was a member of the Sydney Swans' 2005 premiership side as a 21-year-old, but individual recognition took longer.
The versatile backman earned his first All Australian selection last year, in his 10th season, and he has finished third in the Saints' best and fairest for the last two seasons.
Despite having played in five Grand Finals – two with the Swans and three (including the 2010 replay) with St Kilda – he remains one of the game's lower profile A-grade players.
Serious knee and Achilles tendon injuries meant Dempster missed 26 games across 2009 and 2010, but they also shaped his meticulous approach to physical and mental preparation, voted the Saints' most professional player for the last two years.
"If you're going to take a positive out of having a long-term injury, you do get that time to spend with the professionals and that carries into your football," he said.
"It also makes you realise how lucky you are to be fit and on the park and you just enjoy football.
"It can be a lonely place in rehab. Playing footy on the big stage, you cherish it because those injuries can become season ending and career ending."
Dempster is contracted until the end of 2014 and he said if there was still a role for him in the team and he was still contributing he would definitely play on.
He was adamant, however, that he didn't want to be "a footballer that hangs around past his time".
"I want to be able to leave on a high note knowing that I gave it everything and towards the end it wasn’t good enough for me to continue," he said.
"I was fortunate enough to play in the 2005 Grand Final but it was in such an early part of my career that I probably didn't think I contributed that much towards the win.
"My massive motivation is to get to a Grand Final and contribute to team success. That's when keeps me going."
