The AFL has written to all clubs warning them about salary cap rorts and under-the-table deals on the eve of the trading season.

The league has put all clubs on notice that they will be scrutinised over a range of issues that could be an abuse of the player trading system or the salary cap.

Several high-profile players, including free agent Patrick Dangerfield, are being pursued by a range of clubs. Credit:

Ken Wood, the AFL official responsible for policing player payments, wrote to all clubs and player agents this week about side deals for players and their families.

The warning comes while several high-profile players, including free agents Patrick Dangerfield, Matthew Leuenberger and departing Bomber Jake Carlisle, are being pursued by a range of clubs in what is expected to be an extremely busy post-season.