The 23-year-old has been on trial with the Reds and has done sufficiently well to become a permanent addition.

Sydney-born Susak has starred in Adelaide’s last two Pre-Season Cup encounters and Vidmar sees great potential in the player.

He said: “We’re pretty happy, I was reasonably pleased with what he had to offer in the two games he played.

“What we saw there was something that we could build on and we think he could be a very good player for us in the future.”

Susak, who has been playing in Serbia for first grade outfit Vojvodina, is a strong, quick, aggressive defender who is strong in the air.

Having signed the player on a one-year deal, it means 22 of the 23 available squad slots have now been filled at Hindmarsh Stadium.

The final spot has been left open by Vidmar, who has the option to sign another player when the transfer window next opens.

The cut off date for all A-League squads to be finalised is July 31.