Vidic made a waist-high challenge on Galati's Gabriel Giurgiu, the referee produced the red card much to the surprise of the United defender.
United went on to win the game 2-0 thanks to two Wayne Rooney penalties.
After the game, Ferguson said to Sky Sports News: "He raised his foot and in the context of a lot of referees' interpretation, particularly in Europe, I can see why, but it was very harsh I think.”
When asked if the club would appeal to Uefa, Ferguson replied: "I wouldn't think so, I don't think you win these things."