Tottenham boss Ange Postecoglou does not think proposed plans to trial blue cards for sin-binned players will “make any difference” to the game.
Postecoglou says he “doesn’t understand the urgency” to bring in new rules.
It comes as football’s lawmakers Ifab delayed plans to release information about four proposed trials following talks with world governing body Fifa.
“A football match has a life of its own. There are mistakes, flaws and imperfections,” said Postecoglou.
Players shown a blue card would have to leave the field for 10 minutes and players would be sent off if they received two blue cards, or a blue and a yellow card.
If passed into the laws of the game, the introduction of a blue card would mark the biggest single change in managing player discipline since red and yellow cards came into force at the 1970 World Cup.
However, Postecoglou is far from convinced by the merit of the idea.
The Australian added: “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.
“Most of the other sports are trying to speed up their game and I don’t know why we are trying to go the other way.”