Luton Town, the 2014 Conference champions, have sold the played to Championship Blues after taking a chance on him in 2016.
While another former Hatter who played in Non-League is of course Andre Gray and he secured a £18 million move to Watford last week.
Vassell says the door is never closed and the former White Tigers players says nobody should give up on their dreams.
“The advice I would give to any player is just go for it and work hard,” Vassell said today after being announced at St Andrews.
“If you put in the hard work then you can get to where you want to be. There are so many examples out there.
“When I was with Truro City I was doing some building work. It was something I had to do - and it made me even more driven to get to where I needed to be.
“Jamie Vardy has shown everyone that just because you’re playing in Non-League football, it doesn’t mean big things can’t happen for you.
“Hopefully I can achieve half of what he did and do really well in the Football League. I’m so excited by the opportunity.”