Cassio, who was born in Rio de Janeiro, came to Australia in June 2007 to play for the Reds and in three years he and his family have fallen in love with the country.
FIFA rules stipulate that a player born in one country can play for another national team if he has never represented his country of birth at any level and he has lived in his adopted country for five years and become a citizen.
Cassio, provided he obtains Australian citizenship, would be eligible to don the Socceroos' jersey in June 2012 just in time for the start of the qualifying phase of the 2014 World Cup in his native Brazil.
And with Australia struggling to solve its old problems on the left side of defence and midfield, solid Cassio could prove to be a vital option for coach Holger Osieck.
"I would be very proud to play for Australia," left-sided Cassio, 30, told The World Game.
"It obviously is very hard to play for Brazil but I do consider Australia my second country now and I would love to wear the green and gold.
"I am Brazilian but I can tell you that I feel 100 per cent Australian.
"Who knows, if I get the chance to play in the 2014 World Cup in my native country that would be my wildest dream come true.
"My contract with Adelaide is up in five and a half months and I have to speak to the club about my citizenship plan.
"I want to stay in the A-League but I need to know what they want from me because if I get my citizenship I would not be considered a foreigner anymore, which is better for the club too."
Cassio and his family comprising wife Juliana and two boys Bernardo, six, and Ricardo, one and a half, have taken to Australia's way of life like fish to water.
"Actually there is not much difference between life in Brazil and Australia," he said.
"The weather and lifestyle are pretty similar.
"Australia, particularly Adelaide, is also safer than Rio. It is a fantastic place for bringing up a family."
Cassio, who appears to be a more settled player since Scott Jamieson left the club for Sydney FC in the off-season, is having his best season since he came to Australia.
He is playing a key role in Adelaide's revival from last season's wooden spoon to sole leadership of the A-League after six rounds.
On Saturday night against Newcastle Jets he was in devastating mood and one of his rampaging runs down the left produced the team’s first goal for Matthew Leckie from a beautifully weighted cross.
The Reds went on to win 2-1 although Cassio almost spoiled his performance with a careless pass that gave the Jets a late consolation goal.
"I had a few great moments for Adelaide especially in the AFC Champions League campaign in 2008 when we reached the final," he said.
"But this season has been good because the team is playing entertaining, attacking football.
"Of course, it helps a lot when you know that you are playing in your favourite position.
"I have played in several roles for Adelaide but I am feeling more comfortable and confident now because left back is my preferred position."