A WRU disciplinary sub committee handed out a three week suspension to Martyn Williams, which will see the flanker suspended until 14th January.
He will be available again for selection for the Blues Heineken Cup match against Bourgoin on 20th January.
Speaking after the hearing Martyn Williams said,
It was the first time Ive been shown the red card in 12 seasons of playing rugby at senior level.
"Consequently I feel it was out of character and obviously I regret the incident. Id like to apologise to all concerned.
"I was disappointed with my reaction in the match but I fully accept the findings of the disciplinary sub committee.