AFL clubs will be able to submit up to three players for medical examination ahead of the return of the Mid-Season Rookie Draft on May 27.

The pool of players who nominate between April 29 and May 3 will be sent to clubs on May 6 and they will have two days to work out who they want tested.

The independent medical testing will take place five days before the draft on May 22, with club medical staff invited to attend.

AFL.com.au understands all clubs were briefed on the rules in the past week for the latest incarnation of the mid-season draft after more than a 25-year hiatus.

There are 14 positions available League-wide, factoring in player retirements and season-ending or long-term injuries, but clubs must first apply for those players to be placed on the inactive list. 

The number of players selected at this year's Mid-Season Rookie Draft remains to be seen, but industry estimates a range from about 10 up to 25.

That follows the 15 footballers who received AFL lifelines after the introduction of the pre-season supplemental selection period, which ran from December 1 to March 15.

There is a theory in the industry that clubs may encourage veteran players to retire earlier and may look to move those with medium-to-long-term injuries onto the inactive list sooner.

This would enable clubs to have more mid-season draft selections, where they could look to pick a readymade player for immediate help or someone who has emerged as a long-term prospect.

Sources believe key-position talent will be in greater demand than midfield or smaller types, with teams generally well stocked in that department. 

The key Mid-Season Rookie Draft criteria includes:

- Clubs must have a rookie-list spot available or a registered inactive player to be eligible to participate in the draft

- If an inactive, injured player is fit to play before the season ends, a club can apply to return that player to the primary list in place of another long-term injured player

- Players must have nominated for the most-recent National Draft or previously been on an AFL list

- Players who have committed to another year with a Northern or Next Generation Academy are ineligible

- A delisted player can't be re-selected by the same club in the period following their delisting

- A retired player, such as Cyril Rioli, or a player who delists himself must be out of the AFL for at least one full season to be eligible

- Players must submit their contract terms when nominating

- A player on a short-term contract ending on October 31 the same year receives a minimum of $50,000, with a further $20,000 if they are not re-signed or picked up as a delisted free agent

- A player on a contract that ends on October 31 the following year is subject to the same terms as any other player

- An AFL club can re-sign a player as per the current rookie-list rules, otherwise the player becomes a delisted free agent

- The AFL will send the full nomination list to all AFL clubs and state league bodies

- An AFL club must pay 50 per cent of any advance payments to a drafted player's previous club before they are eligible to play a game

- Drafted players who stay in their original state cannot play against their former club unless all parties agree

- A player can return to their former club for finals if their services are no longer required by the AFL club that drafts them