VIDEO: Thompson wary of wounded Sky Blues

Melbourne Heart FC will again be forced to reshuffle when it faces Sydney FC this Sunday, but midfielder Matt Thompson believes Heart's can illustrate strength in depth against the Sky Blues.

Melbourne Heart FC will again be forced to reshuffle when it faces Sydney FC this Sunday.

But midfielder Matt Thompson believes Heart can illustrate strength in depth against the Sky Blues, despite the side losing three key players due to Qantas Socceroos duties.

Richard Garcia, Aziz Behich and Michael Marrone are likely to make the final cut for the Socceroos East Asian Cup 2013 qualifying tournament and therefore will miss the Heart's Sunday afternoon clash at Allianz Stadium.

“We-re not too sure which way we-re going to go yet but the players that have come in have played with us before, it-s nothing new for us to have players that have been called up for Socceroo duty over the last couple of years," Thompson said.

“We think our depth is pretty good to be honest.”

Likely replacements in the back-line are teenagers David Vrankovic and Sam Mitchinson, while Nick Kalmar, Steven Gray, Dylan Macallister and GolGol Mebrahtu could all come into the picture for potential selection and starting berths.

Thompson highlighted that while Heart has been playing good football in patches, the side has lapsed in focus and has struggled to maintain concentration for the full 90 minutes, contributing to a run of disappointing results.

“It-s just that lack of concentration for that couple of minutes where we-re making mistakes and it-s costing us," Thompson said.

"Even [if we make] half a mistake and we-re getting done for it at the moment.

“We-re definitely heading in the right direction. It-s just the little one-percenters that are costing us at the moment.”

Those one percenters were drummed in at a gruelling conditioning session earlier today, which focused on eliminating small mistakes and polishing Head Coach John Aloisi's game plan under the scorching Melbourne sun.

While both sides are in desperate need of a win to lift themselves off the bottom end of the ladder, Thompson said that the side is confident it has the potential for better results.

“For 75 to 80 minutes we-re fine…we know what we-re doing is the right thing; our shape is good, we-re not really getting broken down in terms of being outplayed which is a good thing," Thompson said.

“We just have to worry about ourselves and hopefully we can close them down.”

While Thompson admitted Heart were concentrating on its own preparation, the midfield general was looking forward to the challenge against Sydney's superstar Alessandro Del Piero - but hopes he doesn't perform to his usual standards on Sunday.

“I hope he has a bad one to be honest. He-s been pretty fantastic…but they can lose, that-s fine with me," Thompson said.