AFL football boss Greg Swann has written to all 18 clubs warning that sanctions could follow if teams make mass selection changes for round 24, the final round of the home-and-away season, with finals looming (ABC News).

Swann's memo, sent on Monday, reminded clubs of their "obligation to perform to one's merits" — the AFL's phrase for fielding fit players rather than resting them en masse to keep stars fresh for September (ESPN).

The timing is delicate. Since the AFL introduced a pre-finals bye in 2016, the top eight have had a week off before September. But the finals system now effectively operates as a top-10 competition due to the wildcard weekend, where teams ranked seventh to tenth must back up and play the following week. The top six rest before qualifying and elimination finals begin on September 3 (ABC News).

That split creates an obvious dilemma for teams locked into the wildcard round. The six sides above them get a break. They do not.

Western Bulldogs coach Luke Beveridge pointed exactly to that gap, noting that the six teams above seventh all get a week off while wildcard-bound sides face the prospect of backing up week after week (ABC News). Melbourne coach Steven King, in his rookie season in charge, said he would make any decision "best for the football club and the management of its players" (ABC News).

Two senior coaches publicly pushed back against the memo on Monday night footy shows, saying they will act in their club's best interests regardless of the AFL's warning (Code Sports).

History offers ammunition for both sides. In 2013, Ross Lyon made 10 changes to Fremantle's side for the final home-and-away round. The Dockers were thrashed by St Kilda, then won a historic qualifying final in Geelong — the first visiting team to beat the Cats at the venue in years. Two years later, Brad Scott rested nine North Melbourne players ahead of the 2015 finals. The Kangaroos lost to Richmond in round 23, beat the same opponent in an elimination final, and won a semi-final in Sydney (ABC News).

Both examples are more than a decade old. The wildcard round is new, and it changes the calculus. A team resting players in round 24 now risks entering a knockout game underdone, with no second chance.

For fans, the tension is real. Nobody wants to watch a round 24 dead rubber where a club fields what amounts to a reserves side. But nobody at a club facing three straight must-win games to reach a Grand Final wants to burn their best players in a match that does not change their ladder position.

Swann's memo puts the AFL's position on the record. Whether any club tests it — and whether the AFL follows through — will play out over the next two weeks.