ADELAIDE key position player Nathan Bock could sacrifice a potential All-Australian centre-half back crown as his side searches for a solid offensive structure.

Bock, who started his career at centre half-forward, played in attack in last weekend's win over the Swans and finished with 13 touches, nine marks and two shots on goal.

This week's opponent, Carlton, boasts a dangerous yet smaller forward line which could release Bock to work alongside Simon Goodwin, Kurt Tippett, Jason Porplyzia and Nick Gill.

"I’m not sure where I’ll play at this stage," Bock said on Wednesday.

"I did a little bit of stuff up forward at training today, so I suppose it just depends what Neil (Craig) feels I’m best suited to do this week.

"My preference probably this year would be to be playing centre half-back, but I do enjoy going forward. It’s always good to kick a few goals and wherever I’m playing, I’m enjoying.

"If I’m enjoying it then I’m not complaining either way.

"If you look at the weekend, I suppose Craigy feels I’m probably more needed up forward, so I’m happy to fill any role I’m needed for.

"I need to do what’s best for the team and, if we’re winning, then I’m happy to play wherever."

The Crows should have a settled line-up going into Saturday’s big clash at AAMI Stadium, a rarity this season, with only utility Kris Massie (virus) ready to return.

Brent Reilly (knee), dogged by injury this year, was restricted to running laps at Wednesday’s main training session and will not play at any level this weekend.

Trent Hentschel should be free to represent Woodville-West Torrens having overcome a hamstring strain, while Bernie Vince is expected to play despite falling foul of a chair at ETSA Park on Monday and gashing his leg.

Defender Graham Johncock, who was last week omitted for poor form and failing to meet the necessary standards of preparation, is unlikely to be considered despite being named among the Port Adelaide Magpies' best players on Saturday.

Bock said he'd already noticed a "bit of a change" in Johncock over the past week.

"I think just the way Graham accepted it [was impressive]," he said. "He still stayed positive about it and accepted it.

"He trained really well today and his attitude on the weekend with the Magpies showed that he’s got plenty of character, he’s willing to make a change and wants to get back into the side as soon as possible.

"I suppose the selection will end up coming down to the coaching staff as well as the players. When the players start to see some improvement, on and off the field, then he will come up for selection.

"I’m probably not at liberty to say [when Johncock will return], so I don’t have much more to say on the issue. It will be kept amongst the playing group and coaching group."