Terence Crawford’s reign as boxing’s lone undisputed champion was short-lived.

The IBF ordered Crawford to fight mandatory challenger Sergei Lipinets but with little interest in the fight, the Omaha native passed and instead officially vacated his 140-pound belt on Thursday.

Crawford, also the RING champion, probably will soon relinquish his three other sanctioning-body titles too: He told reporters after he stopped Julius Indongo to collect all four alphabet belts on August 19 that he planned to move up to welterweight.

To fill the vacancy, the IBF has ordered Lipinets and Akihiro Kondo to meet, and both have indicated in writing they want the fight. The sides have until September 30 to come to an agreement. If they can’t, a purse bid will be ordered at that time.

Lipinets (12-0, 10 knockouts), a former kickboxing champion, was also an accomplished amateur boxer in Russia. He fights aggressively and has displayed impressive power since turning pro in 2014. He has stopped durable fighters Cosme Rivera, Walter Castillo, Leonardo Zappavigna and Clarence Booth.

All 36 of Kondo’s professional bouts have taken place at the same venue: Korakuen Hall in Tokyo. He’ll likely venture to the U.S. for the Lipinets fight, his first title shot. The lightly regarded Kondo (29-6-1, 16 KOs) has reeled off eight wins since an April 2005 decision defeat to Ricky Sismundo in an eight-round bout. Most of Kondo’s fights have been scheduled for just eight rounds. Still, IBF officials have somehow deemed him worthy of fighting for a world title.