Tim Bradley has been forced to vacate his world championship after opting to fight Manny Pacquiao for the third time.
The WBO had ordered that Bradley (33-1-1-KO13) defend his welterweight title against mandatory challenger Sadam Ali, but he has instead chosen to meet Pacquiao (57-6-2-KO38) in April to decide a rivalry which stands at one win apiece.
Bradley and Pacquiao, who will box at the welterweight limit of 147lbs, will not officially contest a world championship but the WBO will give "special recognition" to the winner due to the magnitude of their fight. Both previous fights had the WBO welterweight belt on the line.
Bradley stated: "To accept this fight invariably means I cannot comply with my mandatory obligation and must forgo the mandatory against Sadam Ali, as ordered by the WBO.
"This is a difficult decision, but one I have to make to give fans the best fights as well as allow myself the toughest and biggest fights possible."
WBO president Paco Valcarcel replied: "You have been an outstanding, honourable and loyal WBO junior-welterweight and welterweight champion of the world and the doors of the WBO will always be open for you.
"Finally, I am pleased to inform you that we are preparing a special recognition for the Pacquiao vs Bradley III winner - two remarkable fighters and worthy ambassadors to the WBO. Wishing you all the best."