North Melbourne onballer George Wardlaw is expected to miss up to a month after he suffered a hamstring strain against Hawthorn in Round 18.

Wardlaw returned to the line-up having been rested for the Kangaroos' Round 17 game against Geelong, only to be substituted out of Sunday's game at Marvel Stadium.

The young midfielder arrived at the club with an extensive recent injury history but a modified pre-season program and a stretch of games in the VFL prepared him for his first AFL opportunity in Round 10.

"Scans revealed a standard hamstring strain yesterday, (but) he's testing really well clinically, and he finished a lower-leg session in the gym this morning (Tuesday)," head of performance Kevin White told NMFC Media.

"He's pretty upbeat, but we'll take a conservative approach and extend him out to that three-to-four-week (recovery) timeline."

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Forward Cam Zurhaar will be up against it in his hopes to return this season, having hobbled off the ground on Sunday with an ankle syndesmosis injury.

"Cam has suffered a moderate-grade syndesmosis injury," White explained.

"He'll be in a moon boot for the next two weeks and he’ll get reassessed from there, but at this point it looks like a five-to-six-week injury for him."

A second concussion this season will see ruck-forward Callum Coleman-Jones miss at least two weeks as he goes into "enhanced protocols".

"Callum is still really symptomatic, so he'll be away from the club getting monitored off-site by the doctor for the next couple of days," White revealed

In his first senior game of the season, White and the Roos took a "conservative approach" with young defender Jackson Archer, after he reported some hamstring tightness in the fourth quarter which ultimately ruled him out of the contest.

"He felt confident in it but with his assessment on the bench we didn’t want to take the risk, especially with where the game was at and the games Jackson has missed due to injury this year," he said.

"He had a clean scan yesterday, so he'll be available for this week."

Liam Shiels has pulled up "really well" after he appeared to have suffered a serious midfoot sprain against the Hawks.

Co-captain Jy Simpkin has been ruled out of this weekend's clash with St Kilda and will be reassessed heading into Round 20 against West Coast, having been concussed for the second time this season in the game against the Cats.

Veteran midfielder Ben Cunnington (calf tightness) will face a test later in the week, having been withdrawn prior to the reserves' match against Box Hill.

Flynn Perez will also need to prove his fitness this week after a knee injury forced him out of the Round 18 side.