The AFL's interchange cap stops coaches doing their job and will be a risky stab in the dark if it's permanently introduced, says Hawthorn coach Alastair Clarkson.
The cap - of 20 interchanges per team per quarter - being trialled this pre-season was used for the first time in the Western Bulldogs' comeback 1.10.6 (75) to 2.8.8 (74) win over Hawthorn on Friday night.
Clarkson said the maximum of 80 rotations per game, compared to an average of 131 across the competition last year, defied common sense and meant almost all his time was taken up planning and monitoring bench moves.
"You're not coaching," he said.
"All you're doing is counting the number of times players are coming off the ground.
"We want to coach the players in terms of what's happening on the ground, not worry about counting numbers.
"I could get a school kid to do that but the coach is having to do it.
"It's an enormous constraint."
The AFL won't introduce the cap for this year's season proper but is considered likely to do so next year.
Clarkson said if there had to be a cap, 120 rotations would be a more sensible limit.
He hoped the AFL would have a change of heart over the next 12 months, saying locking in the current trial rules could hurt a game that doesn't need fixing.
"There's not a person in the land that knows what's going to happen to the game when that happens," he said.
"I reckon that's an enormous risk to take with what's a pretty good game we've got at the moment just on a hunch.
"We're going to say let's put the cap at 80 and see what happens to the game.
"I hope it's good but what happens if it's no good?"
Bulldogs coach Brendan McCartney agreed the cap of 80 was a bit extreme and too much time was spent counting.
But he was happy for the AFL to use the pre-season competition to experiment, provided they consulted with clubs on how it worked.