The 24-year-old's signing is subject to him being released by Victoria Premier League side Preston.

With experience in the old National Soccer League in Australia, Erdogan can play in any position across the back and brings pace, agility and strength to the squad, complimenting the signings of fellow defenders Shaun Ontong and Brazilian Cassio.

"To be signed by a club like Adelaide United is brilliant and for the time I was there on trial the players and the club were excellent," said Erdogan, who is expected to arrive in Adelaide on Monday.

"Coming to Adelaide my goals are to win the championship and really stand out in the league but at the moment I'm just wrapped to be joining Adelaide United and it will be a fantastic opportunity."

Erdogan underwent a week long trial with United prior to the squad's three week break and Coach Aurelio Vidmar was pleased with what he saw.

"We had a look at him a couple of months ago and he was very impressive," said Vidmar.

"We watched him several times in Melbourne and he will give us a lot of flexibility across the defence."

Erdogan was recommended to Vidmar by original Adelaide player Goran Lozanovski, who is the current coach of Preston, while he has also played under new Reds assistant coach Phil Stubbins.

Adelaide will feature in the 2008 AFC Champions League after reaching the A-league Grand Final last season where they suffered a 6-0 defeat to Melbourne Victory.