OF ALL the pieces in the North Melbourne puzzle, perhaps Drew Petrie might just be the most important.

In 2007 the big man showed not only how versatile he can be, but how crucial that versatility was to the Kangaroos.

While the names Wells, Grant or Thompson might ooze more appeal to some fans, it has often been Petrie’s contribution that has proved decisive in the wash-up.

His ability to swing from end to end and play a variety of roles gives coach Dean Laidley added flexibility – something every team needs if it wants to go that extra step.

Petrie had his best season in 2007, playing all of North Melbourne’s 25 matches.

He was fifth in the club’s best and fairest award in a season in which the Roos finished third, and booted 38 goals.

Given that return – and especially given he bagged hauls of seven and six goals in consecutive weeks last year – one could reasonably expect Petrie would again feature prominently in the Kangaroos’ forward set-up.

But he says he is likely to be only a bit-player in attack this season, instead focusing on a more permanent role in defence.

“I’ve trained every single session in the backline over summer,” Petrie told kangaroosfc.com.au.

“I still expect to do a bit of goalkicking practice during the week just in case I get thrown in the forward line.

“But with Thommo (Nathan Thompson) and then Aaron Edwards improving as well, we’ve got enough talls up there I suppose.”

After roaming free up forward last year – and with good success too – one might think Petrie would be reluctant to switch to the other end of the ground.

But he is welcoming the change.

“I don’t mind going forward and getting a chance to kick some goals as well, I enjoyed that and I got some confidence from last year of kicking a few goals,” Petrie said.

“But I would prefer to stay there [in the backline].”

Petrie was at it again in his side’s round one encounter against Essendon, shifting from defence, to the ruck and up forward.

“When Corey Jones went down we sort of needed another bloke to go through the forward line, and Scott Lucas went down for them so it meant there was one less tall forward for us to man up on,” Petrie said.

“That meant I had to push into the ruck a little bit which was unexpected.

“I planned and expected to play in the backline for most of the day but I’m happy to roll with those punches when those sort of scenarios arise in games.

“But I expect to play [in the] backline most of the year, most of the games.”

Like many of his teammates in the Kangas’ 55-point loss, he had a limited impact against the Bombers but could play a far more crucial role this week when his team meets a pumped-up Richmond.

The 25 year old is uncertain of his exact role but knows he is “in the mix” to play on star Tiger forward Matthew Richardson, something he knows won’t be an easy assignment should he get the job.

“He’s just an absolute powerhouse,” Petrie said.

“It might take two or three of us to hold him back … he runs miles and miles.

“I saw he ran about 17km on the weekend, so I’ll be putting my feet up and relaxing before the game!”