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Five dismissals scarred the weekend's round of English Premiership action while two players have been sent off in the Six Nations -- Ireland's Peter O'Mahony and Zander Fagerson of Scotland.
Rugby authorities are cracking down on dangerous play, especially involving the head, in an effort to reduce episodes of concussion.
England on Sunday resumes its Six Nations title defence in Cardiff, where a win for Wales would give it the Triple Crown following victories against Ireland and Scotland.
The visitor opened its campaign with a shock defeat to Scotland before beating Italy.
"The only thing we can control is making sure we are disciplined in our practice in terms of the height of our tackles," Mitchell said.
"That gives players a better chance to not be sanctioned, but ultimately you still really want to be dominant in your contact."
Wales assistant coach Jonathan Humphreys acknowledged that any contact with the head risked a red card.
"You need to keep reminding of the ramifications of any head collisions," he said. "We work very hard at that in training to be technically as good as we can.
"It's everything we were advised on before the tournament. Referees want to clamp down on it, especially with everything that goes with concussions, and we were aware of it from the off."
Wales head coach Wayne Pivac has steadied the ship after a six-Test losing run during his first year in charge and they are one of only two teams still capable of winning the Grand Slam, alongside France.
The team's injury situation has improved significantly.
Pivac was without a quarter of his original 36-man squad through injuries or suspension for the Murrayfield appointment with Scotland earlier this month.
But backs George North, Jonathan Davies and Johnny Williams are set to be available, with only scrum-half Tomos Williams (hamstring) currently sidelined.
Humphreys said wing sensation Louis Rees-Zammit would be able to cope with close attention from England.
The 20-year-old Gloucester speedster has made a spectacular start to his international career, scoring four tries in six Tests.
"Any threatening player is going to come with a huge tag on top of his head, so we are expecting (Rees-Zammit), among other players, to be targeted," said Humphreys.
"Louis has made massive improvements in his game, and he knows a lot of those English players, so with that comes a huge amount of pressure.
"But he has got a great temperament and we back him to deal with anything that comes his way."