Vidic was sent off against Liga de Quito in the Final of the Club World Cup on Sunday for elbowing Claudio Bieler.
“The sending off made it difficult for us,” said manager Sir Alex Ferguson. “Half an hour to go is a long road with 10 men but Wayne scored a magnificent goal.
“He [Vidic] swung an elbow right in front of the referee and if you do that you have no chance. The referee was absolutely correct.
“We have been informed if there is a suspension it will be European Cup.
“It was a soft sending off. But it depends how Fifa interpret it and how Uefa act in terms of the information they get.
“I’m disappointed because we were in a comfortable position at the time. Vidic is disappointed in himself.”
He added: “In 30 years you’ll look back and see Manchester United’s name on the trophy – although I won’t be around to enjoy it.”
