Australian midfielder Dimitri Petratos has completed his transfer to K League club Ulsan, ending a three-and-a-half year stint with Brisbane Roar.

Ulsan confirmed the signing of Petratos on a three-year contract on Tuesday, with the 24-year-old joining former Newcastle Jets full-back Lee Ki-je at the two-time K League champions.

According to reports, Brisbane will receive a transfer fee that they will split with Newcastle Jets, who had signed Petratos for the next three A-League seasons.

Transfer news: Aussie duo now free agents

Having also previously played for Sydney FC, Petratos leaves the A-League after 124 matches and 20 goals.

"I'm glad to join a team that represents Asia," Petratos said in a statement.

"It's new experience for me. I want to play as soon as possible."

Petratos' departure leaves Roar short-handed for their AFC Champions League (ACL) play-off against Shanghai Shenhua on Wednesday, with the attacking midfielder having left Brisbane's squad in China on Monday.

Brisbane will have one less substitute than usual, as they did not take any extra players with them to Shanghai.

Ulsan have their own ACL qualifier on Tuesday when they host Kitchee of Hong Kong.

If Ulsan and Roar both win their play-offs they will meet in Group E of the ACL.

Meanwhile, Dario Vidosic and Michael Thwaite are both free agents after negotiating releases from Liaoning, who signed Robbie Kruse and James Holland last month.