The AFL has approved a medical substitution just a day out from the 2021 season opener.
Clubs will have a 23rd man in their squad but that player will only be activated into the match if there is a game-ending injury.
A club medical officer will determine if a player is unfit to continue.
The idea originated around concussion, after the league in January tightened rules over medical head knocks, but coaches were unanimous in wanting a substitution for any serious injury.
AFL football boss Steve Hocking unveiled the last-minute change during a press conference at the MCG on Wednesday.
“The health and safety of each player in the game remains the priority and the introduction of a medical substitute ensures that player safety remains paramount in our game,” Hocking said.
“On behalf of the AFL, I thank all senior coaches, the AFL Doctors’ Association and the AFLPA (Players’ Association) for their input and consultation as part of this decision.”
The substitute will be confirmed 60 minutes prior to a game starting and can only be chosen from the listed emergency players.
The AFLPA has been critical of the move, declaring any change to playing numbers in a game-day squad should have happened much earlier.
“This was a foreseeable problem when the rule changes were made last year around rotations, the man on the mark rule and the return to normal quarter lengths,” AFLPA boss Paul Marsh told SEN.
Blues coach David Teague backed the change.
“I think they have added the sub to be make it fairer if you lose a player, so why limit it to concussion?,” he told reporters on Wednesday.
Under new rules, if an AFL player is deemed to have a medically diagnosed concussion they will now automatically be sidelined for 12 days.
Between 2011 and 2015, the AFL cut the interchange from four players to three but a substitute was allowed into the game for any reason.