Of all the fights that Saul “Canelo” Alvarez has to choose from, the IBF is digging in on forcing him to negotiate with its lightly regarded mandatory challenger, William Scull, going as far Monday as to order a June 6 purse bid meeting at its New Jersey offices.

In a Monday letter, IBF President Daryl Peoples wrote that undisputed super middleweight champion Alvarez (61-2-2, 39 KOs) and Cuba’s Scull (22-0, 9 KOs) were ordered on May 13 to begin negotiations for Alvarez’s IBF title defense.

Nine days later, Scull representative Hagen Doering reported that an agreement “could not be reached,” according to Peoples’ letter, and he requested an immediate purse bid.

The IBF has ordered the purse bid for noon Eastern Time on June 6, informing promoters that bids are due by 11:45 a.m. that morning.

Scull, 31, who fought eight consecutive bouts in Germany before posting an eight-round unanimous decision win over little-known Sean Hemphill on the pre-pay-per-view undercard to Alvarez’s May 4 unanimous decision triumph over Jaime Munguia at T-Mobile Arena in Las Vegas, is an opponent who pales in comparison to those Alvarez has been linked with for his next fight.

In fact, Peoples conceded to BoxingScene on Monday that he’s still not absolutely certain that the IBF is first in line among the four sanctioning bodies for Alvarez’s next mandatory defense.

Earlier this month, WBA President Gilberto Mendoza told BoxingScene that his unbeaten mandatory challenger, Edgar Berlanga, is first in line.

Alvarez prefers fighting on the weekends of Cinco de Mayo and Mexican Independence Day (mid-September), so the likely target date for a mandatory bout would be Sept. 14.

Peoples told BoxingScene he plans to contact Mendoza on Tuesday to firm up which body’s mandatory is next in the Canelo sweepstakes.

“I believe the IBF is next,” Peoples said in a text message.

If he’s mistaken, there has been additional speculation that a Berlanga fight makes more sense to take place in New York, not Las Vegas, in consideration of Berlanga’s Brooklyn roots.

Additionally, Saudi Arabian boxing power broker Turki Alalshikh has spoken of Alvarez meeting unbeaten three-division champion Terence Crawford should Crawford claim a fourth division belt Aug. 3 when he meets WBA junior middleweight titleholder Israil Madrimov in Los Angeles.

An Alvarez-Crawford bout could take place in December or January.

Of course, the prized opponent for Alvarez is unbeaten former super middleweight titleholder David Benavidez (28-0, 24 KOs), who will meet former light heavyweight titleholder Oleksandr Gvozdyk in a 175-pound co-main event June 15 in support of the Gervonta “Tank” Davis-Frank Martin WBA lightweight title fight at MGM Grand in Las Vegas.