ADELAIDE coach Neil Craig says the club can't afford to lose defender Phil Davis, amid claims by Collingwood president Eddie McGuire that the 20-year-old is a target for Greater Western Sydney. 

Speaking on Triple M radio on Thursday morning, McGuire said he had "very strong" mail Davis was poised to join the Giants as an uncontracted player next season.

The former top-10 draft pick, who had season-ending shoulder surgery in May, has been offered a new contract with the Crows, but is yet to re-sign.

Davis is the third Adelaide player, alongside forward Taylor Walker and best and fairest winner Bernie Vince, rumoured to be in the sights of GWS.

Walker has been the most strongly linked of the three, but opinions are divided on whether he's received a formal approach from the AFL's 18th team. 

Losing Davis would be a cruel blow for the Crows, who groomed the unflappable backman as a replacement for centre half-back Nathan Bock when he announced he was leaving the club to join Gold Coast on a lucrative deal late last season. 

Adelaide has also been hamstrung in defence by the loss of veteran Scott Stevens, who was forced into premature retirement last month because of the lingering effects of post-concussion syndrome.

Promising key-position players Daniel Talia and Luke Thompson have received opportunities through the injuries to Davis and Stevens, but are still raw in terms of experience, having played only 13 matches between them.

Craig said it would be detrimental to the team to lose Davis, Walker or Vince.

"I don't want to lose Phil Davis," Craig said on Thursday.

"It would be the same if we lost Taylor Walker.

"At the moment Patrick Dangerfield is holding down one of our key-forward positions, so we don't want to lose Taylor either. I want Taylor back in form, so he can continue his AFL career and improve at the rate that I think he can.

"We'd be worse off without Taylor, and it would be the same for Bernie Vince.

"We can't afford to lose any of those players, but we are [helpless] because of the rules.

"If Greater Western Sydney decides they want one of those players and can convince one of those players to go, we can't stop them.

"We certainly can't compete against GWS financially … as a club we've seen it happen [with Nathan Bock]."

Much of the speculation regarding GWS has centred around Melbourne midfielder Tom Scully, who has been offered a multi-million-dollar deal to become the face of the League's newest team.

Like Scully, Davis is only 20 years of age and has played fewer than 30 games.

Most of Gold Coast's uncontracted player signings last year were experienced players in Bock, skipper Gary Ablett, Campbell Brown and Josh Fraser, but GWS has apparently targeted emerging stars with longer left in the game.

Craig said in hindsight the committee responsible for devising the concessions for the Giants and Suns should have put restrictions on the type of uncontracted player the two teams could sign, to keep players like Davis and Scully off limits.

"I think there will be lots of questions asked as it unfolds, just as there will be some questions raised about free agency when it unfolds … anything new is never perfect," he said.

"We could lose a 20-year-old [Davis], who has played 18 games. At least with Nathan Bock he had given the club some really great service and it becomes a bit more palatable to your supporters because they understand.

"It's exactly the same situation with Tom Scully and Melbourne. All your planning, all your development [is gone] for no return.

"Even though Scully is a very good player at the moment, you can imagine what he's going to be like in another three or four years.

"Melbourne, maybe, won't even get to see that."

The Crows flew to Melbourne on Thursday ahead of their clash with St Kilda at Etihad Stadium on Friday night.

Defender Graham Johncock has been cleared to play his 200th match, while young forward Jack Gunston has been recalled to the team to replace injured defender Matt Jaensch (shoulder).

Jaensch will have scans on his shoulder next week to determine whether he needs season-ending surgery.

Katrina Gill covers Adelaide news for afl.com.au. Follow her on Twitter: @AFL_KatrinaGill