The Sydney Swans defence has been resolute throughout 2011, but key backman Ted Richards believes the defensive unit faces one of its biggest tests this weekend against Carlton.

The Swans defence is ranked fourth overall in the competition and in recent times has limited the influence of some the games’ most daunting attacks led by Jonathan Brown and Jack Riewoldt.

Richards says the Swans defence will use its versatility to counter the Blues attack at Etihad Stadium this Sunday afternoon.

“I think the defence needs versatility because they’ll be throwing ruckman down there, sometimes they’ll be going short, and they’ve certainly got some speed down there,” Richards said.

“I think the real strength of our defence this year has been our versatility. Players like Heath Grundy can play on smalls, and Marty Mattner can play on talls, so whatever Carlton throw at us, hopefully we’ll be able to combat it.”

The defensive aspects which are fundamental to the Swans game remain strong. The Club is the leading tackling team in the AFL and is ranked third for tackles inside the forward 50.

Aiding the defensive consistency is the fact the Swans back six regulars of Richards, Heath Grundy, Nick Smith, Rhyce Shaw and Marty Mattner have missed just one match through injury this season.

Richards says while the Swans defensive unit is improving as they string more games together, he has been particularly taken by the performance of Alex Johnson in his debut season.

“The way Alex Johnson has come into our backline in his first year has been really impressive.

“Alex, Heath and myself usually play on the taller forwards and through that, Heath and I do a lot of work with Alex and just let him know his role and try and work out the matchups,” Richards said.

With the Swans training warm-up forced indoors this afternoon due to Sydney’s inclement weather, Richards said the team was looking forward to taking to the drier surface at Melbourne’s Etihad Stadium this weekend.