DREW Petrie thinks he approached this season with the wrong attitude.

"I've been very inconsistent this year. I've probably expected things to carry on a little bit from last year without putting the effort in," Petrie told AFL.com.au at Aegis Park on Thursday.

Last year, the North Melbourne co-vice-captain enjoyed perhaps the best season of his 12-season career. Playing almost exclusively as a key forward, Petrie kicked a career-high 48 goals from 21 games and finished third in the competition for contested marks during the home and away season (49) to earn his first All-Australian selection.

He did it all after overcoming three separate breaks of his feet that sidelined him for all bar two games in 2010.

Petrie, 29, has started 2012 more slowly. And the inconsistency he speaks of is reflected in his goalkicking stats - he had kicked only nine after six rounds, but has rebounded with eight in the past fortnight.

But when Petrie says he expected to cruise through this season, it's best to take his comments with a shaker of salt.

When the AFL Record did a feature story on him last season, past and present teammates branded Petrie one of the most professional players they'd encountered. His commitment to getting the best out of himself had long been renowned, they said.

So Petrie's assessment of his 2012 mindset seems simply a harsh mark from a tough taskmaster.

Just consider North assistant coach Darren Crocker's comments two weeks ago.

"Drew knows that he's not in the best of form but he'll keeping working hard to turn that around because he is a pro," Crocker said.

North coach Brad Scott also suggested this week Petrie had not been helped this season by the Kangaroos' inability to find another key forward to support him, or by the delivery he had received at times.

Later in our conversation, Petrie is prepared to cut himself some slack too.

As disappointing as North's losses to the Western Bulldogs and Port Adelaide have been in the past two rounds, Petrie has been encouraged by his own improved form, particularly his five-goal haul against the Power.

"The last couple of weeks have been a little better," Petrie says. "But in saying that I'd rather get no goals and win than kick five and lose."

Petrie also concedes a key forward's job description has changed markedly in recent seasons. Where goals were once almost their sole key-performance indicator, defensive pressure, creating space for fellow forwards and pushing up the ground to provide a marking option at half-back are now key parts of the job, he says.

"Full-forwards who start inside 50 and lead up at the ball all day are not as prevalent as they have been over the years," Petrie says.

"Forwards haven't been kicking the bags they used to because they've got a wider role these days. And teams prefer to have a spread of goalkickers now."

Individual goalkicking tallies are down across the competition this season. After eight rounds Adelaide's Taylor Walker leads the competition with 23 goals. At the same time last season Richmond's Jack Riewoldt led the AFL on 29 goals. This season, Riewoldt has matched Petrie's 17 goals.

Petrie's workplace has also been one of constant change as the Kangaroos have searched for the most effective forward-line mix. Of North's marking forwards, Petrie and Aaron Edwards (16 goals) have been the mainstays, while ruckman Hamish McIntosh (seven) and Todd Goldstein (two) have rotated through there regularly. Robbie Tarrant (three games and no goals) and Ben Warren (one and one) have also been tried.

Petrie says there is room for three tall forwards and a ruckman on North's forward line provided they meet two conditions.

"A tall forward line can work as long as we're being used and taking our marks," he says.

"We've also got to put forward pressure on when the footy hits the deck and not just be lumbering giants trying to chase little blokes off half-back.

"We probably haven't been able to do that when we've played four or five tall forwards including Todd and Hamish. So Brad's had to throw the mix around a bit."

As part of North's leadership group, Petrie feels responsible for the Kangaroos' two-point loss to Port last Saturday, particularly their inability to stop the Power's run of five unanswered goals in the final 17 minutes.

"As a leader in those moments that's when you need to stand up," Petrie says. 

"The coach always says that the buck stops with him but in 10 minutes of footy it's the players' responsibility, especially the leadership group's responsibility, to change the trend. And we weren't able to do that."

But in football you have to move on quickly after a loss. And Petrie says this Sunday's game against the Brisbane Lions offers 12th-placed North (3-5) the chance to get its season back on track.

"The season has been slipping away from us a little bit over the past few rounds," he says.

"But we’ve got two really big games before the (round 11) bye, 'Brissy' and Hawthorn. Win those and we're suddenly looking a whole lot better."

Nick Bowen covers North Melbourne news for AFL.com.au. Follow him on Twitter @AFL_Nick

The views in this story are those of the author and not necessarily those of the clubs or the AFL