Madaschi, who was one of five Jets players snubbed by the club after the failed bid to dethrone coach Phil Stubbins, agreed to a mutual termination deal earlier on Friday along with midfielder Billy Celeski.
Beyond the A-League he has played in the Korea Republic, Italy and Scotland and has five caps for the Socceroos, scoring two goals.
Madaschi also represented Australia at U-17, U-20 and U-23 level
The towering centre-back heads to Pirtek Stadium as an injury replacement for midfielder Nick Ward, who suffered an anterior cruciate ligament injury in the final moments of the Wanderers clash against Melbourne Victory last Friday.
Madaschi joined his new team-mates on Friday and will train with the side in preparation for Saturday's match against his former club.
