HE MAY be the fourth-oldest player in the AFL, but North Melbourne's evergreen key forward Jarrad Waite isn't showing the effects of father time, says coach Brad Scott.

Waite sits behind only Shaun Burgoyne, Aaron Sandilands and Dale Morris in the seniority stakes, but the 35-year-old is still a key member of the Kangaroos' attack with 10 goals from five games this season.

While he couldn't fault the veteran's form, Scott said the club is monitoring Waite closely to make sure he doesn't succumb to injury like he has in previous seasons.

Shoulder and hip injuries restricted Waite to just 10 games in 2017, while a hip complaint hampered him in the second half of 2016.

"We take enormous amounts of data, we screen, we take strength measures daily. It is measured so closely, we can tell when there's a slight drop-off, and 'Waitey' isn't showing anything like that at the moment," Scott said on Friday.

"I think there's probably a time in the year where we'll take a pre-emptive strike (and rest him) to make sure he stays fresh and healthy.

"But the facts are, over the last couple of years, around the middle of the year he's been hurt, and it's hurt us as a result.

"We're watching him very, very closely."

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Scott's cautious approach to player management may be a result of the Kangaroos using just 24 players so far in 2018.

While they lose star playmaker Shaun Higgins to concussion for Saturday's clash with Port Adelaide at Etihad Stadium, Scott praised the work the club's medical and conditioning team for helping give him plenty of options at the selection table.

"That's not to say I hate them when players are injured either," Scott joked.

"It makes things so much easier (because) we had the luxury of resting Luke Davies-Uniacke last week, (and) then he comes back into the side.

"It just means you have a lot more tools at your disposal, and what's lost in losing players, is the domino effect.

"We lose Shaun Higgins this week, but that might have a flow-on effect to the rest of our structure as well."

A player the club's medical staff would know well is Paul Ahern, as two knee reconstructions in as many years have prevented the former Greater Western Sydney midfielder from making his AFL debut.

After being taken by the Giants with pick seven in the 2014 NAB AFL Draft, Ahern injured his right knee twice in 2016 – in February and September – and North took the Under 18 All Australian knowing he would not play a game at any level in 2017.

Scott said 21-year-old wouldn't be far away from senior selection after being named as emergency for the clash with the Power.

Scott put defender Sam Wright in the same selection equation, with the 27-year-old returning to form in the VFL after serious ankle injuries over the past two seasons had restricted him to just eight games.

"(Paul's) in our emergencies, so he's close," Scott said.

"We've got two guys in that category, Sam Wright and Paul Ahern, who haven't really played senior footy for two years, but they're playing good footy in the VFL.

"I think they're pretty close, but not quite ready this week.

"They won't be far away."