Lustica's contract was set to expire at the end of the season but Adelaide have now confirmed the 22-year-old is free to ply his trade elsewhere, despite refusing to do so initially.
The agreement paves the way for Lustica, who missed Adelaide's 2-1 defeat to the Wellington Phoenix on the weekend, to return to Brisbane having enjoyed a 12-game stint with the dual A-League champions last season.
Lustica arrived in Adelaide from Croatian side HNK Hajduk Split ahead of the 2013/14 season and made 15 appearances for Josep Gombau's men.
It was only a matter of time before Lustica departed Adelaide after the midfielder angered Reds officials by announcing his intention to return to Brisbane.
The former Gold Coast United man had been expected to re-sign for the South Australian team after reportedly agreeing a contract extension.
But he had a change of heart once Brisbane made a play for his services, notifying the club of his desire to reunite with Mike Mulvey.
"We spoke with him two weeks ago and arrived at an agreement. After that he decided to leave," Gombau told reporters earlier this week.
"We need to arrive at an agreement that will be good for him and for us. Sometimes it is difficult as what he wants is not what we want."
Adelaide blocked the move, a decision that clearly incensed Lustica.
Lustica failed to train with his team-mates ahead of their trip to New Zealand and his whereabouts was still unknown once they touched down in Auckland prior to Saturday's match.
His behaviour and failure to train made his position at the club virtually untenable, according to Gombau.
"For me, when one person says they want to stay then changes their opinion and doesn't come to training it is difficult," Gombau said upon his arrival in Auckland on Friday.
"A guy who acts like this doesn't benefit the group. Everyone needs to have rules and if you miss them it makes it difficult.
"After that I honestly don't feel that he can come back and play with us."
