For a student of the backline, Cam Mooney has been quick to learn the art of teaching forwards about earning their kicks. The pre-season experiment of playing the wayward forward down back has been such a success that he will start there against St Kilda on Saturday night.

His aggression at man and ball provides more grunt to a backline fast becoming recognised as one of the best in the competition.

And if Mooney's enthralling Wizard Cup Grand Final duel with Aaron Hamill is any indication, the big Cat has found his niche in defence and opposition forwards are in for a torrid time.

"He is one of those players who won't take any s---. He will stick up for his teammates; he's good to have around,'' acting captain and defender Brenton Sanderson said yesterday.

"He is a big guy and the more big bodies you have around on your side the better. He protects the ball carrier and can be intimidating for opposition players.

"As you are walking down to pick up your man for the first time you are certainly walking a couple of inches taller with him beside you.''

Backline coach Brendan McCartney says 24-year-old Mooney brings much more than a fear factor to the backline.

"He gives us that third tall defender, we have three high quality bigs now and not a lot of clubs have got that,'' McCartney said.

"As a club if you have more depth, more match-ups you can throw at the opposition it makes it harder for them.''

Mooney's shift to defence came as a surprise even to him after he spent most of the pre-season training to play forward again.

"A week before the games started, I asked Bomber (Thompson) if I could have a bit more of a run on the ball and he said `no we're actually going to try you down back for a bit','' Mooney revealed.

"I thought about it and said `yeah, why not'. It (my career) needed to be heading somewhere, it was only going down there for a while.

"I am enjoying it down there now. I have walked into a solid defence with Sanderson, Scarlett, Harley, Rooke and Milburn. They have made it pretty easy for me.''

The success of Mooney's move will in part be measured by how he controls his aggression this season.

Being part of a team within a team can only help, McCartney says.

"Matty and Tom and Sando have had a big influence on him and settled him down and he has embraced that,'' he said.

"If he slips up he lets them down and in a very tight group nobody wants that.

"Plus he has always felt the need to play well; a responsibility to do well and you get that do-or-die role in the backline.''

Sanderson said he was proud of the camaraderie within the backline and like any newcomer, Mooney had to earn his place.

"The guys that play down back are all different people outside footy but when we come together on match day we gel,'' he said.

"It is no secret we have been tight the last five seasons and once you come into our group you have to rise to a certain degree of expectation and he (Mooney) has done that so far.

"He has taken his criticisms well and is learning the craft quickly. He still has a few things to learn but so far he has shown he is willing to listen.

"You know that he won't shirk an issue and will give his best and that's the level of commitment we expect from everyone.''