Adelaide United has signed Brazilian defender Cassio in a move calculated to strengthen its defence, the Australian A-League side said on Wednesday.

Adelaide United coach Aurelio Vidmar said the inclusion of Cassio - full name Jose de Abreu Oliveira - would add balance to the team.

"Cassio has a strong left foot, he gets up and down the line, has good pace, puts in a good cross and is well-suited for the A-League style of play," Vidmar said.

"He's an exciting type of player who will attract people to the game. We've been very selective in the type of player we wanted to sign and we're looking forward to having a player of his quality here in Adelaide."

The arrival of the 27-year-old comes shortly after the departure of another Brazilian, Fernando Rech, who failed to reach terms with last year's beaten A-League grand finalists after two years at the club.

Cassio is a product of the youth system Rio de Janeiro's CR Flamengo club and has played club football in Brazil, the US, Paraguay and Brazil.