With veteran defenders Pascal Bosschaart and Adam Griffiths still on the injured list, Calver is expected to figure just one day after his 17th birthday when Sydney take on Melbourne Heart at Allianz Stadium on Sunday.

Already the centreback has experienced the highs and lows of A-League football, with a sorry 3-0 capitulation to Adelaide United at home followed by a gutsy come from behind 2-2 draw away to Perth Glory.

Sydney are now desperate for three points to salvage their finals hopes and quietly-spoken Calver, who is in no hurry to return to the ranks of the youth league, is optimistic.

“We need to get points on the board so we get a run in towards the finals,” he said. “Everybody is confident; everybody knows that we can do it. We’ve just got to get out there on the weekend and prove it.

“[Against Perth] I thought we were the better team. I thought we could have won the game actually. We were coming home much stronger than them.

“That’s what all the boys learned from the week before against Adelaide when we kind of dropped our heads. So we just kind of stayed calm and kept going.”

Calm is the operative word. Despite his tender years, the Joey’s defender has shown plenty of savvy and on-field composure while mixing it with the league’s older and more battle-hardened troops.

Yet it wasn’t until former Sydney FC coach Ian Crook got hold of him at the NSW Institute of Sport that Calver even realised he could forge a career keeping goals out rather than banging them in.

“He just threw me in the backline one day and decided that he liked me there and that was that,” Calver said.

“It’s good. It was a big change but in saying that you also want to be up the front scoring goals too. You get a goal every now and again.”

There are benefits in knowing how the other half play.

“As a former striker you know how the opposition will be like at the back,” he said. “You can kind of read what the strikers are going to do because you used to be one.”

Farina has described his teenage ring-in as a quiet lad with a good attitude. But as the former Wollongong Wolves player has discovered, getting thrown in the deep end is one thing – learning how to swim there is quite another.

“I got called up because of injury so as soon as those boys come back I know I’ve just got to be working harder to try and keep that chance and cement a spot after that,” he said.

“[The youth team] are all curious to know about it because they all want to make the step up to. There’s been a few of us now who’ve done it. So they’re all keen and putting in the hard yards too.

“I think it shows you have to grab your opportunities when they come.”