CALE Hooker is set to be graded as an unrestricted free agent, leaving Essendon unable to match a rival's bid for the key defender if he chooses to leave the club at the end of the year.  

The banned Bomber becomes a free agent at the end of this season after his suspension ends for taking prohibited substance thymosin beta-4.

AFL.com.au believes Hooker is set to qualify only as an unrestricted free agent under the AFL's rules, meaning Essendon will not be able to match a rival bid. 

Fremantle has already been linked to presenting a long-term deal to the All Australian backman and best and fairest winner.

It means the 27-year-old is not in the top 25 per cent of earners at Essendon this season. He last signed a three-year deal with the Bombers in 2013.

Had Hooker qualified as a restricted free agent, Essendon could have matched any bid to keep him at the club.

If Hooker had still wanted to leave after the Bombers matched, he would have been forced to do so through a trade. As an unrestricted free agent he will be able to take up a rival's offer without Essendon having a chance to match the deal. 

If Hooker chooses to leave the Bombers they can still be compensated through a draft selection – which would likely come after Essendon's first pick.

It means the Bombers could finish the year with two picks in the first three selections should they finish in the bottom two on the ladder. 

Former Melbourne defender James Frawley was an unrestricted free agent in 2014 and crossed to Hawthorn. The Demons gained pick No.3 as compensation, with which they drafted bright midfielder Angus Brayshaw. 

The Bombers pushed to trade Hooker in 2012 when West Coast strongly pursued his services, but as a contracted player the West Australian wanted to stay in Melbourne.  

He has flourished since, becoming one of the premier key defenders and leading intercept markers in the competition.

Hooker was one of a group of suspended Bombers, plus Western Bulldogs forward Stewart Crameri, who trained in Melbourne this week under the guidance of former Essendon assistant coach Sean Wellman.

The banned Bombers take to the training track this week. Pictures: Getty Images