"He accepted a violent conduct charge following an off-the-ball incident during yesterday's game against Southampton, but argued the suspension was excessive," the FA said in a statement. "This was rejected by a Regulatory Commission."
Although referee Craig Pawson missed the indiscretion when it happened, television cameras captured Young elbowing Southampton midfielder Dusan Tadic in the stomach.
Young's absence could be costly given Manchester United's recent form. The club has drawn its past three league fixtures and lost 2-1 to Bristol City in the quarterfinals of the Carabao Cup.
Missing two key players in Young and Lukaku isn't the way Manchester United will have wanted to start the new year.