Born in Perth, the Serbian-Australian was a shock inclusion in the preliminary squad, ahead of this month's international friendlies against Norway and Colombia.
Susnjar first broke onto the scene after featuring in Ante Milicic's starting XI across all three of Australia's Under-23 group matches at the AFC U23 Championship in China earlier this year.
After a brief spell with FK Teplice in the Czech Republic, the left-footed central defender's efforts on the international stage earned him a move to fellow Czech outfit FK Mlada Boleslav during the January transfer window.
The 22-year-old has played 17 games for Boleslav across all competitions this season alongside his fellow teammate and former A-League striker Golgol Mebrahtu.
Despite his young age, Susnjar has played in Lithuania, Serbia and Romania and will hope his regular game time in Europe will be enough to make van Marwijk's final 23-man cut, set to be announced next week.