Matthew Spiranovic and Alex Wilkinson are likely to face some stiff competition during the lead-in to the AFC Asian Cup, with Trent Sainsbury desperate to earn a place in the Socceroos' starting XI.
Alex Wilkinson has been a regular since being handed a late-career international debut by Postecoglou, who has also experimented with Nikolai Topor-Stanley in recent friendlies.
Bailey Wright and Ryan McGowan were overlooked for the Asian Cup, leaving Sainsbury and Chris Herd to push the incumbent duo in training.
"I want that spot to be mine," the PEC Zwolle man said.
"I'm not shy about saying it. Someone's got to sit on the bench and I don't want it to be me. I want to be there for that first game and get the three points for the boys."
Asked how he intends to earn a starting berth, Sainsbury joked: "I bought Ange a couple of Christmas presents.
"Just work hard in training and it's all up to the boss," he added.
Wilkinson meanwhile, fresh from winning the K-League title with Jeonbuk Motors and earning a place in the Korean Team of the Season, insisted he has been given no indication by the coaching staff of the likely central defence.
"To be honest I've got no idea," he said.
"We haven't done too much tactical work yet because we've waiting on the rest of the squad to get in.
"The competition's good, we all want to play obviously, but there's only two spots there. The competition for spots is going to be good, not only at centre-back but in the whole squad.
If Spiranovic and Herd fall behind in the pecking order, there will be two former Central Coast Mariners defenders paired together for the the Socceroos at a major tournament, a prospect that excites Sainsbury.
"Me and Wilko have got a great bond and it'd be great to see two Mariners boys out on the pitch together," he said.
"I never thought we'd both be there playing together in an Australian squad. To play at a big tournament like this with him would be magical."
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