The AFL has blocked a left-field trade proposal involving Essendon ruckman Paddy Ryder's move to Port Adelaide as a free agent, leaving the Bombers and Power to restart negotiations. 

The two clubs approached the AFL to investigate whether Ryder would become a free agent if he and Essendon mutually voided his existing contract, which runs until the end of 2016.

Under this scenario, Essendon would receive a free agency compensation pick based on Ryder's age (26) and the length and value of the contract offered by Port. 

Port Adelaide would then trade its first-round selection (No.17) to the Bombers in exchange for two later picks. 

AFL.com.au understands the AFL would not allow the deal to proceed if a second, separate deal for a combination of picks or players was required to satisfy both Port Adelaide and Essendon. 

If Ryder was to reach the Power via free agency, that move could not be supplemented by any separate trade between the two clubs.   

The plan to simply make Ryder a free agent, however, is yet to be publicly ruled out by the League.

It was expected the Bombers would receive a compensation pick at the end of the first round (No.21 overall) if Ryder left as a free agent. 
 
Rival clubs, which would then move down one position in the draft order after Essendon's pick No.20, have complained to the League about that prospect. 

The two clubs have been unable to negotiate a regular trade sending Ryder to Alberton, with the Bombers not satisfied with Port Adelaide's offer of pick No.17.  

Ryder could yet seek to activate a breach-of-contract clause and become a delisted free agent, and it appears this is influencing Port Adelaide's view of a fair trade.

There was a precedent for the proposed Ryder free agency ploy last year, when St Kilda and Nick Dal Santo agreed to void the final year of the midfielder's contract, which had been triggered when he passed a medical test.

The Saints received a second-round compensation pick (No.25) for Dal Santo.