The WBC on Monday ordered a mandatory lightweight title fight between its champion, Shakur Stevenson, and No. 1 contender, William Zepeda, sources told The Ring.

The sides have 30 days to negotiate, and if no deal is struck by May 6, the fight will be scheduled for purse bid.

The development comes after Stevenson (23-0, 11 KOs) revealed Saturday on social media that he rejected His Excellency Turki Alalshikh’s offer to fight Zepeda this summer.

“Turki promised me a number and now he going way back on that number that he promised me and sending his towel boys to run me the info … Mr. De La Hoya now let’s negotiate,” Stevenson wrote. “ … I’m still champion and aren’t pulling out of anything. If we can’t reach a deal then purses it is.”

The WBC was still determining the purse split, sources said, as this went to publication. Stevenson’s side requested 70-30 in favor of the champion while Golden Boy Promotions asked the WBC for a more favorable 55-45.

Stevenson, after rejecting Alalshikh’s final offer, stands to earn 70 percent less if he proceeds with the purse bid process depending on what split the WBC determines, sources said.

Stevenson, of course, can always opt to relinquish the title if he’s not satisfied with the outcome of the process. The 27-year-old, who fights out of Houston, is The Ring’s No. 1 lightweight. He’s coming off a ninth-round stoppage over fringe contender Josh Padley in February in Riyadh, Saudi Arabia.

Padley accepted his first title challenge during fight week. Stevenson was set to fight contender Floyd Schofield, who withdrew with illness. That was Stevenson’s first bout after wrist surgery that scrapped a title defense vs. Joe Cordina in October in Riyadh.

Stevenson is The Ring’s No. 4 lightweight. Zepeda (33-0, 27 KOs) is No. 5.

The 28-year-old Mexican volume-puncher has reeled off two consecutive wins over former champion Tevin Farmer in closely contested fights.

Zepeda’s most recent win over Farmer, earlier this month in Cancun, Mexico, was more clear than his decision win in November in Riyadh when he was floored.