VETERAN North Melbourne forward Drew Petrie continues to enjoy the strong backing of coach Brad Scott despite his run of indifferent form.

Scott admits the 33-year-old's return of 19 goals from 15 games this season has been below expectations.

But the coach left little doubt where he stands on Petrie's place in the side when asked if he had considered dropping him.

"Not for one second," Scott replied.

"But (our forward) unit hasn't been working to the level that we would expect (of late) ... Drew's only a part of that. He's a significant part but he's only a part, nonetheless.

"So we're looking at all of our forward line players to improve and to work a bit better together but the baseline of Drew's game is the way he defends and that is just incredibly underrated outside our football club. But it's incredibly highly rated inside it.

"Any external comments about Drew are irrelevant to us."

North have been in free fall recently, losing five of six games to go from top of the ladder after 12 rounds to eighth heading into round 17.

The Roos face an improving Port Adelaide at Etihad Stadium on Saturday, with the Power their nearest challenger three games behind in ninth.

Key trio Daniel Wells, Jarrad Waite and Nick Dal Santo return from injury and illness in a significant boost to the side.

But Scott confirmed emerging forward Mason Wood will miss up to two months of football after undergoing knee surgery.