THE LEADING ruckman in this year's NAB AFL Draft won't be available to Gold Coast or Carlton as a mature-age pick after the AFL clarified rules for the clubs.

Under the notice given to clubs on Monday, the League said the Suns would get access to three players and Carlton two players "who have previously nominated or been eligible for the draft or been previously listed with an AFL club".

However, this raised questions from clubs about players such as 19-year-old All Australian ruckman Kieren Briggs, who was eligible for last year's draft but overlooked before returning this year to be named the best big man of the under-18 championships.

Briggs is also a member of the Greater Western Sydney Academy, meaning the Giants could have lost first call on him if the Blues and Suns had priority access to all players who had gone through undrafted.

But AFL.com.au understands the AFL has tweaked the mechanics of the special assistance package for the clubs, with players who appeared at the NAB AFL Under-18 Championships this year, plus northern Academy and Next Generation Academy players all exempt from the Suns' and Blues' grasp.

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Others who fall into the same group as Briggs include Noah Answerth, who played for Vic Metro this year as an over-ager and captained Oakleigh Chargers to their TAC Cup Grand Final last weekend, as well as Vic Country pair Matt McGannon and Laitham Vandermeer, who will also attend the Draft Combine next week.

West Australian prospect Luke Foley is another who would have been in that group if the AFL had not changed its original rulings that meant 19-year-olds who had nominated for the draft last year had been eligible to join the Blues or Suns.

Gold Coast put forward the plan to be able to recruit mature-age players before other clubs in a bid to add experience to their list, with the AFL Commission knocking back requests for priority picks.

The Suns want to recruit the players to provide senior bodies to help their younger group, but the Blues appear at this stage more likely to trade out the pre-listed players they pick up.

This has caused some discontent among clubs, with the Blues given an extra chip to do deals during the trade period in comparison to the Suns.

Werribee forward Josh Corbett is seen as a likely pick up for the Suns, but the ability for the clubs to on-trade him to other teams could see rival clubs make appealing bids to the Blues to sign Corbett and then move him on.