ROOKIE-LISTED ruckman Shane Mumford has left Geelong to begin life as a Sydney Swan, however, the Cats have been successful in their bid to land Fremantle defender Marcus Drum.

Mumford has agreed to terms with his new club with the Cats handed a second-round pick (No.28 overall) in next month's NAB AFL Draft, while selection 49 is now Fremantle's.

Drum has played just 22 games for Fremantle since being taken at No.10 in the 2005 NAB AFL Draft but football operations manager Neil Balme saw room for the 22-year-old in Geelong's line-up.

"We see Marcus as a versatile player that can fit into our structure," Balme told geelongcats.com.au. "He has played some good games at Fremantle and we feel that his best football is still ahead of him.

"He was a top 10 draft pick just four years ago, and has talent and a good work ethic, and sees the opportunity to play as the most important thing given our tight salary structure."

In further movement, the club received selections 40, 42 and 56 in return for No.33 - which has been tied up in a Shaun Burgoyne deal also involving Hawthorn and Essendon.

For Geelong, Mumford's exit is a blow given the club identified the 23-year-old when he was playing country football for Bunyip and put significant development efforts into him.

However, the Cats have finally taken a hit for three years as the AFL's best team, with salary cap constraints putting the squeeze on their premiership-winning list.

"The reality is that we could not and would not compete with the dollars that Shane has been offered," Balme said.

"It's well known that we want to keep our group together and all of the players have accepted that to do that they have to forego bigger offers from other clubs to achieve that goal.

"Shane has chosen not to do that, and while we are disappointed to see him go, we will not deviate from our philosophy."

Mumford had been on a rookie contract in 2008 and 2009 but is believed to have been offered a four-year deal with the Swans worth more than $1 million.

He played 18 games this season, after three games in his debut year, and worked hard to fill the void created by injured teammate Brad Ottens.

Mumford becomes the first rookie in history to be traded during the exchange period.

In late August, the AFL announced that new regulations would permit rookies to be traded onto the senior list of another club, encouraging greater movement of players during the post-season. They were previously ineligible.

Geelong's first five selections in the 2009 draft are now 17, 28, 40, 42 and 56, but that order could change if the club takes further part in trade week, despite its desire to keep its list intact.

It's hoping to retain dual premiership player David Wojcinski. Mark Blake and Mathew Stokes may need to wait until the end of this week before signing new deals.