The AFL has warned clubs they face $100,000 fines if they breach new rules regarding poaching of players.
The AFL on Tuesday tightened its rules on a player signing with a new club to try to prevent the code going down the same path as the NRL.
In the NRL players can play out a season with their existing team having already signed a deal with a rival club.
Previously the only way an AFL player could sign a deal with a different club while still under contract was in the "off-season window" where offers could be made to players before the start of the final year of their existing deal.
Now, while clubs can still negotiate with players, no binding deals can be agreed outside a three-week "free agency window" at the end of each season.
Clubs who are discovered to have made a binding agreement with a player outside that window face the hefty fine of up to $100,000.
No players have so far admitted to signing with rival teams in advance, although Phil Davis announced he intended to negotiate with Greater Western Sydney while still playing with Adelaide.
There was also strong speculation over whether Gold Coast's Gary Ablett or the Giants' Tom Scully had committed to their expansion teams a year ahead, although both maintained throughout their final seasons with their first clubs that they were yet to make up their minds.
AFL football operations manager Adrian Anderson says free agency is a big test for the maturity of the competition.
"We were the only sporting competition in the world that had a draft, a salary cap and no free agency for its players," Anderson told reporters on Tuesday.
"The strength of the feedback (from clubs) definitely is we don't want to go down the path of players moving during the season and that's something that we strongly support.
"All the signing of free agents must now occur in the free-agency window which will be a period of approximately three weeks following the end of the season."
Geelong coach Chris Scott, skipper Joel Selwood and Norm Smith Medallist Jimmy Bartel travelled to South Australia last month to talk to Port Adelaide's out-of-contract midfielder Travis Boak.
Anderson says Tuesday's announcement serves to clarify what can and can't occur in such meetings.
"What would have to be proven is that a club had entered into a contract arrangement or understanding with a player," Anderson said of what would be required for a fine to be issued.
"It really is maintaining that rule but strengthening it by way of the sanction, a requirement that you must say that the negotiations are non-binding, and also by closing that window a year in advance for a player to sign up.
"The competition was pretty united that we don't want to go down the track of players announcing that they'll be with another club during the course of the season."