Deontay Wilder recommends that Anthony Joshua not rush back into a fight against Andy Ruiz Jr. and adds that it's not over for Joshua. (1:43)

The IBF on Tuesday granted unified heavyweight world titleholder Andy Ruiz Jr. an exception to his mandatory defense, which will allow him to defend all three of his major belts in the planned rematch with former titlist Anthony Joshua.

Ruiz (33-1, 22 KOs), 29, of Imperial, California, who pulled a monumental upset on June 1 in New York by dropping Joshua four times en route to a seventh-round knockout victory to win the belts, is slated to meet Joshua (22-1, 21 KOs), 29, of England, in an immediate rematch on Dec. 7 in Diriyah, Saudi Arabia.

Ruiz risked being stripped of the IBF belt without gaining the exception to a mandatory defense that is due against Kubrat Pulev.

On Monday, the IBF board of directors participated in a conference call to vote on whether the exception should be granted or denied. According to the letter that IBF president Daryl Peoples sent to those involved Tuesday, a copy of which was obtained by ESPN, a majority of the board of directors determined the exception should be granted but with certain conditions.

The IBF said that, in granting the exception, that the Ruiz-Joshua rematch must take place on or before Dec. 7.

Also, the IBF said it will require that the winner of the fight must agree in writing that he will face Pulev in the mandatory defense on or before May 31, 2020.

Further, Ruiz "shall agree in writing to indemnify, hold harmless and otherwise reimburse the IBF for any and all legal fees or other expenses related to the granting of said exception, including, but not limited to, the costs attendant to any resultant litigation."

On July 24, Ruiz promoter Tom Brown of TGB Promotions wrote to the IBF to request the exception and paid the $20,000 fee required to request one. On July 31, John Wirt of Epic Sports, which co-promotes Pulev with Top Rank, wrote to the IBF and outlined their side's objections to Ruiz being granted the exception. The IBF weighed both requests and made its decision.

Brown declined comment on the vote, but Wirt was not pleased.

"We plan to appeal this," Wirt told ESPN. "We will appeal the whole thing, but we want the conditions to be clear. One of our concerns is there is no guarantee the Ruiz-Joshua winner will fight Pulev next with no intervening bouts or that the winner will apply for an exception for a unification bout or another type of exception.

"The fact is, I'm not even sure Ruiz has even agreed to this fight being in Saudi Arabia yet. There are a lot of things unknown at this juncture. We plan to review the order and deal with it in due course."

Pulev (27-1, 14 KOs), 38, of Bulgaria, has won seven fights in a row since he suffered a fifth-round knockout loss in a mandatory title shot against then-unified heavyweight champion Wladimir Klitschko in 2014.

Pulev worked his way back to a mandatory position and a shot at Joshua and was supposed to fight him in October 2017. However, Pulev suffered a shoulder injury in training and had to withdraw from the bout. Instead, Joshua stopped Carlos Takam, who had been appointed the mandatory challenger once Pulev pulled out of the fight.

Pulev again became the IBF's mandatory challenger by winning a unanimous decision against Hughie Fury (lineal heavyweight champion Tyson Fury's first cousin) in October in a title elimination fight.