North Melbourne is likely to be without stars Daniel Wells and Jarrad Waite for Thursday night's blockbuster clash against the Crows after the veterans didn't fly to Adelaide with the team on Wednesday afternoon.

Wells suffered an ankle injury in last Friday night's loss to Hawthorn and while coach Brad Scott was "optimistic" the classy midfielder would face Adelaide, he also said the Roos wouldn't risk players if they weren't 100 per cent fit.

Waite aggravated a hip issue against Geelong in Round 12 and later conceded he shouldn't have played against the Cats, although the key forward was hopeful last week that he would get up for Thursday night's crunch match.

North said the pair would fly to Adelaide either tonight or tomorrow if they passed fitness tests and were named in the team this evening.

In a boost for the Roos, skipper Andrew Swallow (concussion) and important midfielder Ben Cunnington (corked quad) are set to return after missing the grudge match with the Hawks.

"I'm definitely playing. I got through training yesterday and was able to do everything I needed to do," Swallow said at Melbourne Airport on Wednesday.

"I was really close to playing last week and it felt good but … we're still learning about concussion and just thought I needed that week to get myself 100 per cent right."

The Roos are dealing with a worrying injury toll as they attempt to arrest a slide of three losses in the past four games, with young defender Luke McDonald's season in doubt after he had hamstring surgery on Wednesday morning.

The likes of Shaun Higgins (knee), Ben Jacobs (foot) and Sam Wright (ankle) are already out long term.

The Kangaroos upgraded rookie Robin Nahas to their senior list on Wednesday. Both North Melbourne and Adelaide’s full teams will be released at approximately 5.55pm SA time.