The romance comes from his grandfather, who played in two premierships with the Blues, and the realisation was that he wasn't 100 per cent committed to the Demons.
McLean played 94 games for Melbourne after he was taken at pick five in the NAB AFL 2003 National Draft.
An ankle reconstruction late last year denied him a decent pre-season, which in turn affected his ability to play to his potential.
With the ankle problem now fully sorted, McLean said a fresh start was what he needed.
"There were a few little contributing factors, but at the end of the day I just felt deep down in my gut that a change would be the best thing for me," he told SEN radio's Morning Glory program.
"If I wasn't 100 per cent happy, and 100 per cent committed to the footy club – which I wasn't – then I thought I was wasting the club's time and I was wasting my time".
The 23-year-old said the family connection wasn't a huge factor, but it had been an emotional consideration.
"There's a bit of a romantic feel to the club – my Pop played two premierships there.
"That wasn't a huge thing that forced me to make my decision, but that little factor made me smile a little bit."
McLean will bring some grunt to a midfield that was criticised towards the end of the season for not working hard enough defensively.
Being reunited with Blues coach Brett Ratten, who was the midfield coach at the Demons when
McLean arrived, was also a factor.
"Brett was our midfield coach in my first year, and he was one of the best coaches I've ever had, so the opportunity to work under Ratts was another contributing factor.
"You know, there's a lot of greats who are down there – Craig Bradley, Robert Harvey – Greg Williams goes down there a little bit and does some work with them.
"I'm nothing fancy, just a workhorse, someone who likes to get their hands dirty and get in and win the footy."
