The limit of 80 rotations per game being trialled this pre-season has already drawn fierce opposition from coaches after just one weekend.
But AFL chief executive Andrew Demetriou said on Tuesday it had already been determined a cap would apply next season, with only the precise number still up for debate.
"The fact of the matter is unless people have got amnesia the AFL Commission has already passed the rule, which it said at the end of the year the cap's coming in," Demetriou told Melbourne's SEN radio.
"They wanted to look at this year to see if the actual number of 80 is correct.
"There's no going back on that. That's already been in place.
"I'm not quite sure why after one round of NAB Cup, everyone's up in arms, they want it reviewed."
The AFL's laws of the game committee last year recommended a cap of 80 be introduced for this season.
That was knocked back by the commission last October.
At the time, Demetriou said the commission wanted to assess another season under the current interchange rules and trial the cap in the 2013 pre-season "before deciding whether to implement a change".
The cap, trialled for the first time in the past weekend's pre-season games, was savaged by coaches.
Carlton coach Mick Malthouse said it was likely to make the injury rate rise, not fall.
Hawthorn's Alastair Clarkson and Port Adelaide's Ken Hinkley both said a cap of 80 defied common sense, while North Melbourne's Brad Scott warned it could force clubs to flood their defences when players tired.
Western Bulldogs player Mitch Wallis said on Tuesday the extra fatigue caused by the cap was noticeable.
"It would be fine for a game but if you had a whole season of that, fatigue would set in and injuries would occur as a result," Wallis said.