Butler lost a 10-round decision on a nine-bout card that was held to benefit victims of the Sept. 11 terrorist attacks on the Twin Towers in New York City. After the fight, which was the final one of the night, the boxers met in what usually ends with an embrace. But Butler punched a stunned Grant in the face with a bare fist and the crowd began to chant, "Lock him up."
The 28-year-old Butler was immediately escorted from the ring and arrested and charged with assault before being released on his own recognizance.
Butler has 20 days to request a hearing for the suspension.
Notable deaths of 2014 [PHOTOS]