One day after unified heavyweight world titleholder Anthony Joshua was formally ordered to make his WBO mandatory defense against Oleksandr Usyk, he was ordered by the IBF on Thursday to make the mandatory defense for that organization against Kubrat Pulev.

The dual orders place Joshua's hold on three of the four major world title belts in jeopardy because he cannot make two mandatories at the same time. That means either one organization or challenger will have to agree to step aside for the other fight or Joshua will have to vacate or be stripped of one of the titles.

Less than 24 hours after the WBO notified the Joshua and Usyk teams that they had 30 days to make a deal or a purse bid would be ordered, the IBF sent letters via email to the Joshua and Pulev camps notifying them that they should immediately begin negotiating that bout.

"Negotiations should commence immediately and be concluded by January 11, 2020," IBF championships committee chairman Carlos Ortiz Jr. wrote in the letter. "If you are unable to come to an agreement for this bout the IBF will call for a purse bid."

If the fight goes to a purse, Joshua, as the titleholder, would be entitled to 65% of the winning bid, and Pulev (28-1, 14 KOs), 38, of Bulgaria, would receive 35%. The fight is worth tens of millions of dollars.

Anthony Joshua easily outpointed Andy Ruiz Jr. on Saturday to regain his titles. Richard Heathcote/Getty Images

Joshua (23-1, 21 KOs), 30, of England, and Matchroom Boxing promoter Eddie Hearn, who also co-promotes former undisputed cruiserweight world champion Usyk (17-0, 13 KOs), 32, of Ukraine, have not specified what their plan is or which mandatory opponent they plan to pursue, but Hearn has been in touch with John Wirt of Epic Sports and Entertainment, which co-promotes Pulev with Top Rank.

The orders come less than a week after Joshua easily outpointed Andy Ruiz Jr. on Saturday in Diriyah, Saudi Arabia, to regain the titles and avenge the monumental upset seventh-round knockout Ruiz authored to take the belts on June 1 in New York.