However, it changes nothing for the Blues, who still have to secure a bonus point victory to have any chance of qualifying after a disappointing 21-3 defeat to Perpignan last weekend.
Cardiff Blues CEO, Robert Norster said: 'Firstly, we are all aware it's our own disappointing performance of last weekend that makes this judgment even an issue for us.
"We are yet to receive any detail of the process other than news of the decision. We naturally await with interest the rationale behind such a finding, as I'm sure will many others in the game.
"The ERC Board's decision to enable Leeds to be awarded the game, together with a four try bonus point and enter our encounter having rested last weekend are obviously matters we and I would imagine other teams in the competition are less than satisfied with.
"We understand the difficulties faced by the ERC in this and other often conflictual decisions they must make and we are not in the best position to offer an unbiased view. However, I believe many will recognise the potentially serious implications of the ruling that run far beyond just this match.
"Nevertheless, we must all put the rights and wrongs of the rugby politics to one side and ensure our focus remains on Sunday's match."