Riley Knight could be a late addition to the Adelaide team if the Crows decide to go smaller to combat the heavy rain that is expected on Saturday.

"You do modify your game in wet conditions," Crows assistant coach Matthew Clarke said.

"You play a little bit more direct and probably a little less handball, but not a huge modification."

Knight is the travelling emergency for the Crows' clash against North Melbourne at Blundstone Arena on Saturday.

The 22-year-old flew out with the team on Friday morning after he missed last week's win against Richmond with a hamstring injury.

Knight played in the first five games of the season, but coach Don Pyke stuck with the 22 players who hammered the Tigers last week.

Clarke said "a number of" players needed to prove their fitness at Friday afternoon's training session in Hobart to show they had overcome the six-day break.

"It has been a short week, so we do have some players that have to get through this final training session," Clarke said.

"It's a six-day week and any time you have a six-day week, the recovery process takes until the last session of the week."

Clarke said vice-captain Rory Sloane should be fine after struggling in the early part of the week with a corked thigh.

Star forward Eddie Betts has also had a light week.

"Eddie Betts will be fine I reckon," Clarke said.

"He's probably one of the guys who we make sure he's 100 per cent, but he's fine.

"He did as much as Eddie needs to do."

Knight averaged 17.4 possessions in the opening five rounds, rotating between the forward line and through the midfield.

"He's obviously unlucky, he was in pretty good form before he went out," Clarke said.

"The team's performed well, and that's just the circumstance we're in.

"He understands that, and I'm sure he's going to be a big part of the season."

With rain expected, Clarke is ready for a tough contest against the Roos.

"I'd suggest internally they probably feel they are playing reasonably good footy," Clarke said of the Kangaroos.

"They've got a pretty potent forward mix and their midfield is elite, they've got great inside midfielders.

"They're going to be a great challenge."