The AFL's free agency window opens for the first time on Monday, with St Kilda's Brendon Goddard heading the list of players potentially moving.
Goddard, who has been strongly linked to Essendon, is a restricted free agent, meaning even if he wants to move, the Saints can keep him by matching a rival's best offer.
In that case, his only way of leaving would be to seek a trade or enter the draft.
The Bombers have reportedly offered a four-year deal worth as much as $800,000 per season.
While Goddard is yet to declare his hand, several players have already told their clubs they want to leave.
Big-kicking West Coast forward Quinten Lynch, a 29-year-old 209-game player who has been linked with Collingwood and Carlton, has walked out.
Lynch is an unrestricted free agent, meaning the Eagles cannot stop him joining the club of his choice.
Port Adelaide defender Troy Chaplin, a restricted free agent, and out-of-favour Adelaide forward-midfielder Chris Knights, who is unrestricted, have both been linked to Richmond.
Melbourne's 2011 best and fairest Brent Moloney, who struggled for regular games under new coach Mark Neeld this year, has told the Demons he is leaving, with several clubs having expressed interest.
Carlton veterans Jordan Russell and Bret Thornton both intend to use their unrestricted status to find new clubs, as does Port Adelaide's Steven Salopek.
Essendon forward Angus Monfries, Melbourne defender Jared Rivers and Geelong fringe player Shannon Byrnes are other potential movers, although have not committed to leaving their current clubs.
Adelaide star forward Kurt Tippett is weighing up a move to a Queensland club, but will have to wait until the trade period starts on October 8 if he decides to switch as he has not played long enough to fit the free agency criteria.
That's also the case for Gold Coast youngster Josh Caddy, who has told the Suns he wants to head home to Victoria.
October 19 is the deadline for players to field offers from rival clubs under free agency, although for restricted free agents their current clubs have until October 22 to match those offers.
The trade period is October 8-26.