A blockbuster deal in which Western Bulldogs captain Ryan Griffen would be traded for Greater Western Sydney's Tom Boyd has been done. Under the deal, which was finalised this afternoon, Griffen and the Dogs' first pick, No.6, goes to the Giants in return for Boyd.

Boyd has been offered a seven-year deal, believed to be in excess of $6 million. Griffen has a four-year deal with the Giants.

While this represents a backdown by the Giants - who had vowed Boyd would not be traded under any circumstances - the club will emerge with Griffen and an extraordinary draft yield of picks 4, 6 and 7.

The Giants are now in a position to trade for pick one from St Kilda.

The Giants understood to have come under pressure from the AFL to acquire seasoned players such as Griffen in order to lift their fortunes.

The argument against doing the deal was the message it would send to its other young stars coming out of contract, but the counter is that there are some within the AFL industry who believe the youngsters will stay if the club is more successful in the next 12 months.

But Giants chief executive David Matthews said the club had changed its position because the trade was "in the best interests of the club".

"First, the Bulldogs have made a revised and attractive offer which now includes their first draft pick (six), an elite player in Ryan Griffen and salary cap assistance in relation to his contract," he said.

"Second, our coach Leon Cameron has consulted the leadership group and they have agreed they want a united and loyal playing group heading into an important season in 2015.

"Third, as a club we are proud to represent Western Sydney and Canberra and it's critical that our players share that value. Clearly Tom doesn't and the best course of action is for him to leave the club.

"We believe this is an excellent trade in the best interests of the club and gives us the best possible chance of achieving success in the coming seasons.

"It significantly strengthens our playing list and gives us picks 4, 6 and 7 in next month's draft which can also be traded.

"We are delighted to have Ryan Griffen at the club. He is not only a great talent but a person with strong values and brings more experience and maturity to the list."

Bulldogs chief executive Simon Garlick said the club was delighted to secure the key forward.

"We know our supporters will be thrilled to see Tom play along-side the likes of Liberatore, Roughead, Wallis, Bontempelli, Macrae, Stringer, Dahlhaus, Johannisen, Hunter, Hrovat, Smith, Roberts and Talia, not to mention Minson, Murphy, Morris and Boyd and the rest our dedicated playing group," Garlick told the club's website.

Griffen's request for a trade to the Giants was the bombshell of the trade period, leading to the exit of Dogs coach Brendan McCartney last Friday.

The 28-year-old had vowed not to return to Whitten Oval despite the removal of McCartney.

Boyd was the No. 1 draft pick last year and is one of three highly-rated young key forwards along with Jon Patton and All-Australian Jeremy Cameron.

The Giants, should they wish, would have the option of drafting a replacement tall forward in Peter Wright if they retain pick four.

However, the club is more likely to select midfielder Christian Petracca if it lands the No. 1 pick.