A protest against any horse which has started in a race, shall be made to the stewards in writing, signed by the protestor, no later than seventy-two (72) hours after the race is declared official excluding non-racing days of the meeting. If the incident the protest is based upon occurs within the last two (2) days of the race meeting, the protest may be filed with the Executive Director of the Board no later than seventy-two (72) hours after the race is declared official excluding Saturdays, Sundays or official holidays. Upon receipt of the protest the Executive Director will assign the protest to an active board of stewards. Protests shall state the specific reason or reasons in such detail to establish probable cause for the protest.