ADELAIDE duo Chris Knights and David Mackay have been ruled out of Sunday afternoon's clash with Richmond at AAMI Stadium, while Patrick Dangerfield could return as early as next week.

Knights (plantar fasciitis) and Mackay (groin) both failed to train on Wednesday and will spend at least another week on the sidelines.

Forward Brett Burton also sat out the session with a sore knee, but will train with his teammates on Friday.

Dangerfield was expected to miss a month of football after breaking a bone in his hand against the Western Bulldogs in round five, but trained one-handed on Wednesday and could push to play against North Melbourne next weekend.

Utility James Sellar (hamstring) and forward Ricky Henderson (hamstring) could also be available for selection against the Roos.

Wingman Brodie Martin joined in non-competitive drills at training, but the club is unlikely to consider him until he completes 12 months of rehabilitation in his comeback from a knee reconstruction.

Wednesday's 90-minute hit-out at AAMI Stadium was the first of two main training sessions for the Crows this week.

The club has scrapped its traditional training program, which involved one long session and one short one, in favour of two medium-length sessions.

Utility Scott Stevens said it would allow the players to train with greater intensity.

"The game is quicker this year and teams are playing with more speed, so we want to practise training with and against that speed," Stevens said.

"We've shortened the sessions, so we can train at that speed and still get the recovery we need to play well on the weekend."

The changes to the training program were introduced as a result of ongoing discussions between the leadership and coaching groups.

While it has been reported that the players drove the decision, Stevens denied that was the case.

"I'm not sure where that (suggestion) came from, but that's not the way it works here. We’re all responsible for our performance as a group, and as a group I mean all the coaches and players in the one group," Stevens said.

"As a leadership group and a playing group we're always looking for ways we can get better. We had to look at everything we were doing and to make sure that if we did change something that we did it for the right reason, and weren't just changing it for change's sake.

"We didn't say, 'We're 0-6, so let's change everything'."