Sydney have admitted the boots worn by debutant Sam Wicks, which played a part in a sickening injury to Collingwood's Isaac Quaynor, were not AFL compliant.
Quaynor ended up with a severe gash on his leg following Wicks' attempted tackle.
After the game, Magpies coach Nathan Buckley said: "(Wicks') studs raked across (Quaynor's) shin and actually split his shin six to eight inches completely open."
Early on Friday, AFL CEO Gillon McLachlan confirmed the AFL was investigating the matter.
Later, the Swans released a statement which read:
"The Swans can confirm that the boots Wicks was wearing were standard issue screw-in boots, that have a hybrid soleplate which includes plastic and aluminium stops. These boots are understood to be widely worn by players across the competition.
"Following discussions with the AFL it has become clear that these boots are not compliant with AFL regulations.
"The Sydney Swans will take steps to rectify this immediately to ensure that all boots are compliant going forward."
The AFL then released its own statement which said the league had written to all clubs to state football boots could not have any form of exposed metal studs or stops.
"The health and safety of everyone in our game, both on and off the field, is always our highest priority," AFL General Manager Football Operations Steve Hocking said.
"Football boots with exposed metal studs have the potential to cause injuries and have no place across any level of our game.
"There are players in the competition who have been wearing boots direct from manufacturers that feature screw-in studs that have a hybrid soleplate, which includes both plastic and aluminium stops, and these are not compliant with AFL Regulations.
"It is the responsibility of clubs and players to work with manufacturers to ensure football boots worn by all players are compliant with AFL Regulations and ensure a duty of care to themselves, their teammates and opposition players.
"Where we can make our game safer for everyone involved, we will."