North Melbourne coach Brad Scott is not confident heading into Friday night's clash with Essendon, acknowledging that his team's up-and-down season makes it hard to predict what type of performance it will deliver.

North is coming off one of its best performances of 2015, having beaten Geelong by 41 points last Saturday night.

However, that win followed a demoralising 55-point loss to Gold Coast, one of North's four defeats by nine goals or more this season.

The 10th-placed Roos have won consecutive games just once this season – in rounds six and seven, against Richmond and Essendon.

Scott told reporters on Wednesday that such a form line meant North could not take anything for granted on Friday night against a 14th-placed Essendon side that has won just one of its past six matches.

"I'm not confident, because if you're confident of [the players producing the right response] you breed complacency and I'm certainly not complacent," Scott said.

"I've got to make sure the players aren't complacent, and to be honest (given) our performances this year, complacency shouldn't be something that we have an issue with.

"So we'll keep driving the standard that we want and we'll look for the evidence the players can give us to get the right results."

The Roos will be without vice-captain Drew Petrie on Friday night after the key forward was suspended for one match for striking Cats defender Andrew Mackie.

Scott said Petrie realised he had let his teammates down with his lack of discipline.

"I think Drew is really disappointed with himself and we've had a quick conversation," Scott said.

"I think it speaks for itself. He's our vice-captain, he let himself down, he let the team down.

"He responded to a pretty minor incident with a pretty foolish response himself, so he cops his right whack."

Scott nominated tall forwards Aaron Black and Mason Wood, and smalls Robbie Nahas and Lindsay Thomas as possible replacements for Petrie.

Black has played just one senior game this year after being a regular part of the Roos' forward mix in 2013-14.

Post-season shoulder surgery and the poor form of Black's VFL affiliate North Ballarat contributed to a slow start to the season, but the West Australian's form has improved steadily in recent weeks.

It was also timely that he played one of his best games of 2015 last Saturday against Geelong's VFL team, kicking three first-half goals and taking nine marks.

Scott said Black had coped well throughout a trying year and was starting to push hard for a senior recall.

"He's been steadily improving all year after shoulder surgery on an injury that really hampered him last year," Scott said.

"We know what Aaron's capable of and we've been reluctant to bring him in until he's discovered his best form, but he's been really encouraging in the VFL, (he's) really hard to defend and he's certainly an AFL player.

"His responses in the VFL have spoken for themselves. It's always very difficult for players when they're less than 100 per cent and he has been a little bit restricted in the early part of the year, but he's now fully fit and his form is reflecting that."

Scott said Nahas (hamstring soreness) and key defender Lachlan Hansen (hip) should be available for selection this round after missing the Cats clash.

The Roos coach also praised the way Brent Harvey responded to being handed the substitute's green vest against Geelong, and did not rule out using him in the same role against Essendon.