North Melbourne fears Luke McDonald could have suffered a serious left hamstring injury, with the young defender being assessed by a surgeon on Monday.

The concerning news comes as Andrew Swallow (concussion), Ben Cunnington (corked quad) and Jarrad Waite (hip) race the clock for Thursday's crucial away clash against Adelaide.

However, star midfielder Daniel Wells (ankle) has pulled up well from the bruising nine-point loss to Hawthorn and should be fit to face the Crows.

McDonald suffered his injury after a team-lifting chase and tackle on Cyril Rioli in the second quarter on Friday night, which affected the Hawthorn superstar's kick just enough so that it hit the post.

While McDonald's effort has come at a cost, Kangaroos coach Brad Scott couldn't confirm if the 21-year-old's season was in doubt.

"Luke McDonald is the major concern there (from the weekend), it's pretty safe to say he definitely won't play this week," coach Brad Scott said.

"He's being assessed as we speak for something we hope is not too serious, but it's serious enough for us to seek a surgical opinion.

"He's the most pressing concern for us at the moment.

"I'm not quite sure to that extent (if his season is in doubt). I made some comments earlier this year about injuries and giving a prognosis and what was clear from those comments was I'm not a doctor.

"I'll wait until we've got definitive answers for you there."

The Roos are hopeful of regaining Swallow, Cunnington and Waite, although back-to-back six-day breaks means the important trio will only have until Wednesday to prove their fitness, after missing the loss to the Hawks.

"Due to the short turnaround I think it will be a tough ask for all of them to get up, especially with our policy right at the moment of not risking anyone who's not 100 per cent," Scott said.

"That being said, all three were pretty close to playing last Friday night but they weren't at that level that we need them to be.

"We’ll assess them probably as late as Wednesday and then make a decision.

"But we've worked really hard to get off to a really good start to the year and we're now in a position where we need to make sure whoever represents the club is 100 per cent ready to go – and we've got the depth to do that."

Scott was "optimistic" that Wells would face the Crows, with the veteran hurting his ankle against the Hawks but playing out the match and pulling up well.

After losing three of their past four matches to flag rivals, the Roos (10-3) need to bounce back against the red-hot Crows (8-4) before the bye.

While losing McDonald is a blow, North was buoyed by Jed Anderson's comeback from a long-term hamstring injury in the VFL on Saturday, when he collected nine possessions in Werribee's loss to Essendon.