Tottenham manager Ange Postecoglou strongly opposes the potential introduction of blue cards and sin-bins in football, stating that it would "destroy" the game.
The proposed trials, which include blue cards for dissent and tactical fouls, with players spending 10 minutes off the pitch, were delayed by football's lawmakers Ifab after discussions with Fifa.
Postecoglou criticized the idea, saying, "Adding another [card] one. What is that going to do? The remedy is already there."
He expressed concern that having a team down to 10 men for 10 minutes would harm the game, leading to time-wasting strategies.
Liverpool manager Jurgen Klopp and Newcastle boss Eddie Howe also voiced skepticism about the proposed changes.
Klopp questioned the source of the ideas from Ifab, while Howe stated that he's not a fan of the new proposals, believing they would add confusion and make the game more stop-start.
Postecoglou questioned the urgency to introduce new rules, stating, "I struggle to understand why there is this urgency all of a sudden to bring in new things.
I don't know if there's much wrong with the game as I see it and why a different colour card will make any difference."
Fifa responded cautiously to the critics, urging restraint, and it's now decided that the precise details of the proposed trials will be confirmed after Ifab's annual meeting on March 2.
Sin-bins, previously used at grassroots levels for dissent, could be extended to cynical fouls as part of the trial.