Undisputed heavyweight champion Oleksandr Usyk has been ordered by the WBO to begin negotiations with mandatory challenger Joseph Parker.
The Ukrainian, 38, unified the division for a second time on 19 July with a fifth-round stoppage of Daniel Dubois at Wembley Stadium.
New Zealand’s Parker beat Zhilei Zhang to win the WBO interim belt in March 2024.
Both parties have 30 days to find an agreement or the WBO will order purse bid proceedings.
Parker held the WBO title between 2016 and 2018, beating Andy Ruiz Jr to claim the vacant belt, but lost it to Anthony Joshua after two defences.
Following defeat by Briton Joe Joyce in 2022, the 33-year-old has won six fights in a row to re-emerge among the title contenders.