ADELAIDE football operations manager Phil Harper says losing promising defender Phil Davis to Greater Western Sydney is a bigger blow to the club than the loss of All Australian centre half-back Nathan Bock to Gold Coast last year.

He said if the Crows had their time again, they would push for less established players to be off limits to expansion clubs.

On Tuesday, Davis told Crows teammates of his intention to leave West Lakes and join GWS next season as the club's first official uncontracted player signing.

Davis' announcement came almost exactly 12 months after his one-time mentor Bock made headlines by becoming the first player to publicly pledge his allegiance to the Suns.

Davis' departure is a cruel blow for the Crows, who had groomed the 20-year-old NAB Rising Star nominee as a long-term replacement for Bock.

Adelaide chief executive Steven Trigg was a member of the committee responsible for establishing the concessions for the AFL's 17th and 18th teams, but Harper acknowledged that younger players should have been off limits to the cashed-up newcomers.

"We were one of the clubs that agreed to the AFL concessions. Did we think we'd be the hardest hit of all the AFL clubs? Probably not, but as it turns out we are," Harper said at a press conference on Tuesday.

"In hindsight, we don't like three-year players, who you put time and effort into and draft with pick No.10 in the [2008] draft leaving our club … but welcome to the new world of AFL footy.

"Our club is bloody disappointed Phil has made this decision. We understand it, but we don't like it.

"When you lose a player who is 20 years old and who we see as a future captain of our club and as a rising star, it's certainly a massive loss on the back of losing another centre half-back last year under similar circumstances."

Giants senior coach Kevin Sheedy welcomed Davis' decision: "I love it when any player in the AFL puts his hand up and says he wants to play for GWS. That's fantastic for GWS.

"I don’t know if it's true, but if it is, I am rapt and I hope there are another 20 who want to follow him. Our job is to look around Australia to find the best footballers to bring to GWS. It took a long time to do it, but we have to get it right once we're there."

Adelaide was disappointed with the compensation - an end-of-first-round draft pick - it received for Bock.

Compensation is determined by a formula that factors in a player's age, AFL experience, career achievements, draft position and the size of the contract offered by GWS or Gold Coast.

Harper expected Davis to be regarded as a 'top-echelon' player, worthy of a pick in the middle of the first round of this season's NAB AFL Draft.

"It was only three years ago we used pick No.10 to pick Phil. I've seen nothing to suggest that wasn't a really good pick," he said.

"The AFL work on first-round picks, middle of first round and end of first round.

"I don't know what the exact formula is, but you'd think if we picked him at No. 10 and he's gone forwards since then and not backwards I would hope we'd get somewhere in the middle of the first round."

Davis admitted money had been a factor in his decision to join the Giants, but refused to give details about his agreement with the club, including the length of his contract or when list manager Stephen Silvagni had first approached him.

Crows teammate Matt Jaensch was more forthcoming, offering this tweet: '@PhilDavis16 has left for a multitude of reasons, 800,000 reasons!'

"He's an idiot sometimes, Matty," Davis said in response to the tweet.

"I'm not going to go into detail, but [that figure is not correct]."

Davis grew up in the ACT before moving to Adelaide with his family as a teenager, and insisted the chance to be part of a new team in a developing market was the main reason behind his decision to leave the Crows.

He denied GWS had given him any guarantees over the captaincy or his role within the team, and maintained he didn't know the names of other players the fledgling club had signed.

"I've had a look at Gold Coast and how they've been going. I can see what they're trying to create and the profile of the squad they want to build," he said.

"I've heard the rumours [about players linked to GWS] like everyone else. I don't have any more to give on that, but if they're true I'm very excited."

Davis has already cleaned out his locker at West Lakes, and will continue his rehabilitation from season-ending shoulder surgery on his own.

The 18-match player denied the change in coaches at Adelaide had influenced his decision to leave, and said the hardest part had been telling his teammates.

"There were a few shocked faces when I told the boys, which I expected" he said.

"This organisation has been really good to me and the people within it have been fantastic. That's probably been the hardest bit … you feel as though you're letting someone down, but that was part of the tough decision."

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