Dal Santo's move to the Kangaroos comes after long-time St Kilda stalwarts Stephen Milne, Jason Blake and Justin Koschitzke retired, while ruckman Ben McEvoy was moved on to Hawthorn in a trade to put more draft picks in the hands of the Saints.
Despite jumping ship, Dal Santo said Saints fans should not be worried.
"I can in one sense (see why Saints fans would be worried), but on the other hand, I'd also have a lot of confidence if I was a St Kilda supporter," he said.
"It relates to the last 10 years, and how good things have been.
"And now it's St Kilda's turn to go through that re-building phase, it's difficult to accept.
"I saw and heard all the frustration throughout the year from St Kilda supporters, questioning where the club's directed, whether the players are trying as hard as they used to."
Dal Santo said the Saints' struggles in the past two years should highlight just how good their period of reaching grand finals in 2009 and 2010 under coach Ross Lyon was.
"I'd like to think as a St Kilda supporter, that you'd appreciate how good the last 10 years has been - obviously without the ultimate success," he said.
"But (the fans should) know that the club does have a direction, led by a new president, they'll be getting a new CEO, Chris Pelchen as the head of football and Scott Watters as coach.
"They are heading in the right direction, there's a lot of young kids coming through that football club which will carry them through the next 10 years just like myself and six or seven of the guys did 10 years ago."
Dal Santo added: "I think St Kilda did handle themselves really well throughout the whole year in regards to blooding young kids, giving them opportunities, playing senior players in different positions so these young guys can get more chances and move the club where they probably need to go."
On the impact of free agency, Dal Santo said it would be 'hypocritical' of players to judge the process they were so keen to bring in - and said over time critics would become more 'understanding' of players' desire to switch clubs after long tenures.
"You can't be hypocritical, and that's one of the risks of what's happened here," he said.
"The AFLPA supported the players in this push for free agency, it's disrespectful to now say it's not working for us.
"As a player we were so focussed on having an option and a choice of where you want to play your football, and I think that was really important.
"And I still do.
"I think free agency is still new, and it's fresh, and received a lot of attention last year - particularly with Goddard leaving.
"I just think it'll become a little bit more relaxed in years to come. I can see it becoming more common."
Nick Dal Santo urges St Kilda fans to keep faith
