Laws designed to protect players are necessary but just how and when they are implemented needs much more scrutiny, veteran Argentina hooker Agustin Creevy said on Wednesday.
England’s Tom Curry received the first red card of the World Cup when he clashed heads with Argentine fullback Juan Cruz Mallia in Marseille on Saturday, for which he has been given an effective two-game suspension as long as completes World Rugby's "tackle school".
England went on to win the game 27-10 despite losing Curry inside the first three minutes thanks to a superb display from their forwards and flyhalf George Ford.
Several other similar incidents across matches in the opening round of fixtures in France went unpunished, and with no explanation forthcoming from officials, it has left a grey area for supporters and players.
"Without a doubt, rugby is changing because of these rules," Creevy told reporters on Wednesday. "It is something that for me should be reviewed a little, because there are times when it (a dangerous tackle) is with intention and sometimes without intention. I don't know how they measure it.
"Obviously I always respect decisions, because that's what they're for (player safety). But it is now very difficult to watch a game without a yellow card or a red one."
Creevy, the most capped Argentine player of all time with 102 international appearances since he made his debut in 2005, said the sport is changing and players must adapt, but in his opinion the speed of the game should be taken into account.
"Obviously the rules are protecting the player from head injuries and I agree with that. But it is a contact sport and to lower your range and height, it is very difficult," he said.
"There are times when it should be measured differently. I'm not a specialist in this, but I feel like we're heading towards a different kind of rugby."
Argentina play their second game in Pool D against Samoa on Sept. 22.