The Gillette AFL Trade Period kicks off on Monday, October 1 with the beginning of the League's first ever free agency period.

How does free agency work?
Players can change clubs without going through the process of a trade or the draft. A concept that has long been a part of American sports, free agents fall in the category of unrestricted or restricted. To be eligible, players must be out of contract and have spent at least eight full seasons at one club.

Click here for the Gillette AFL Trade Period hub

Restricted versus unrestricted
An unrestricted free agent can automatically move to the club of his choice while an offer to a restricted free agent can be matched by his club, which has right of first refusal over his services. A restricted free agent is one that is in the top 25 per cent highest-paid players at his club while an unrestricted free agent is in the bottom 75 per cent or has spent at least 10 years at his club.

Going?
Brendon Goddard has dominated free agency talk all year and heads into the free agency period as the biggest name on the market. Goddard has refused to speak in any detail on his future and has played his cards close to his chest.

Going?
Angus Monfries has attracted some interest from Port Adelaide, with a rumoured four-year deal to tempt him back to his home state. Demon Jared Rivers has been linked to a move to Geelong with Shannon Byrnes said to be heading in the opposite direction. Port Adelaide defender Troy Chaplin has been rumoured to be heading to Richmond.

Gone
Brent Moloney is on his way out of Melbourne after a frustrating first season under coach Mark Neeld. Chris Knights has left Adelaide and Jordan Russell and Bret Thornton are on the way out of Carlton, while Steven Salopek will seek greener pastures after failing to play a game with Port Adelaide this year. West Coast forward/ruckman Quentin Lynch has also flown the coop and is rumoured to be on his way to Collingwood.

Testing the waters
Goddard was the first player to admit he would see what the market says he is worth before committing to his club but others are sure to be following his path.

Pulled the pin
Josh Drummond and Chance Bateman have called an end to their careers as has Geelong star Matthew Scarlett. Antoni Grover, Brad Green, Michael Doughty, Mark McVeigh, Kelvin Moore, Ryan Hargrave, and Lindsay Gilbee have also retired. Jude Bolton is weighing his future after the Swans' premiership.

Off the market
The long and protracted discussions between Travis Cloke and Collingwood reached a conclusion on Thursday when he signed on for five years. Brett Deledio was the next highest profile player to have turned his back on free agency and sign on with his club. The Tigers locked Deledio into a five-year deal back in March. Leigh Montagna also signed a two-year deal with the Saints after some conjecture about his future. Lenny Hayes, Brent Harvey, Sam Mitchell, Simon Black and Steve Johnson all re-signed with a minimum of fuss.

Compensation
Clubs will be compensated by way of draft picks if they are deemed to have a net loss in the free agency period. The compensation falls into one of five categories - a first-round pick immediately following the club's first round pick, an end of first-round pick, a second-round pick immediately after the club's second round pick, an end of second-round pick or a third-round pick immediately after the club's third round selection.

US comparison
Each American sport has its own version of free agency with various detailed and complicated rules.

NBA free agents tend to be third or fourth-year players coming off their rookie contract but there is an exception for free agents that had originally been drafted in the first round as opposed to the second round.

After Gilbert Arenas left the Golden State Warriors to join the Washington Wizards, a rule was brought in to ensure teams over the salary cap couldn't lose a player coming off a rookie contract for huge money. Arenas had been a second-round pick but his performances in his first few years had elevated his standing in the game. The Warriors were unable to match the Wizards' offer but a rule was brought in afterwards to allow teams in their position to have the ability to re-sign restricted free agents who hadn't been first-round picks.

Restricted free agency is only allowed for first-round picks after a team exercises its option for a fourth year, and the team also gives a qualifying offer at the rookie scale amount after that fourth season.

Restricted free agents who were not first-round picks must have served three seasons in the NBA, and his team must have made a qualifying offer for either 125 per cent of his previous season's salary or the minimum salary plus $200,000, whichever offer is higher.

Similarly NFL free agents must have served three seasons but franchises can appoint one player a year to a 'franchise tag'. An 'exclusive' franchise player must be offered a one-year deal for an amount no less than the average salaries of the top five players who play that position or 120 per cent of that player's previous year's salary. The team benefits because the player cannot negotiate with other franchises. A non-exclusive player can negotiate with other teams but his current team has a right to match any offer.

2013

Lance Franklin is set to be the highest profile player eligible for free agency next season along with teammates Mitchell and Luke Hodge. Nick Riewoldt, Jobe Watson, Daniel Wells, Drew Petrie, Adam Cooney and Andrew Carrazzo are some other names that we could be discussing this time next year.

When?
The AFL Free Agency period runs from 9am October 1 to 5pm, October 19. The AFL exchange period runs from October 8 to 2pm, October 26.

Free agency explained

Luke Holmesby is a reporter for AFL Media. Follow him on Twitter - @AFL_Luke