AFL COACHES have endorsed the new concussion substitute rule, but have expressed frustration at its implementation just two days before the start of the season.

The AFL Coaches' Association held its annual meeting at Etihad Stadium on Wednesday as a prelude to the AFL season launch, with 15 of the senior coaches in attendance.

Various hot-button issues were debated, but concussion was high on the agenda, with the group briefed by AFL medical commissioner Peter Harcourt about the new procedures around on-field head injuries.

The coaches' main frustration was that they suggested a concussion sub to the AFL at the corresponding meeting 12 months ago, but it took what they considered an inordinate amount of time for the League to sign off on the rule.

"We would like to have had the opportunity to see how it worked in a game that didn't count for premiership points," AFLCA chief executive Danny Frawley said.

It was explained to the coaches that the new procedures for treating concussion were only agreed to at a conference in Zurich last November and were embargoed for all sports until the start of this week.

The coaches are also seeking clarification about how the rule would apply if a second player were lost to concussion.

As the rule stands, a fit player who might have been previously subbed off the ground for form or tactical reasons would not be able to return in this instance.

The coaches received briefings from AFL chief executive Andrew Demetriou, his deputy Gillon McLachlan and AFL umpires manager Jeff Gieschen.

It also emerged during the meeting that Sydney Swans premiership coach John Longmire made a presentation to the AFL Commission last December at which he explained the way the game and the role of coaches had evolved over the last 10 years.

The coaches resolved to play an active role in the drafting of the charter of the game, which is being prepared by the AFL over the next few months.

They said the charter should be completed before any more rule changes are implemented.

Ashley Browne is an AFL Media senior writer. @afl_hashbrowne