Former middleweight world titleholders Daniel Jacobs and Julio Cesar Chavez Jr. will meet in a 12-round super middleweight bout on Dec. 20, Matchroom Boxing promoter Eddie Hearn announced Friday at a news conference in Los Angeles.

The fight, expected to be finalized for weeks, will take place in Phoenix at Talking Stick Resort Arena — home to the city’s NBA and NHL teams — and is due to headline a card on DAZN as part of Jacobs’ deal with the streaming service for multiple multimillion dollar comeback fights following his decision loss in a middleweight unification fight with Canelo Alvarez on May 4.

“Daniel returns from his points defeat to Canelo to move up in weight on his quest to become a two-weight world champion,” Hearn said. “He faces a determined Julio Cesar Chavez Jr., who looks for redemption at the site of his father’s last-ever professional fight. We expect a great fight, a huge crowd and a stacked card as we’ll look to close out the year in style.”

Chavez (51-3-1, 33 KOs), 33, of Mexico, is the son of legendary boxer Julio Cesar Chavez. Jacobs (35-3, 29 KOs), 32, of Brooklyn, New York, has been a middleweight for his entire 12-year career and is now moving up in weight after struggling to make 160 pounds in recent fights.

“I’ve achieved a dream of becoming a world champion at middleweight and now I am seeking to secure my legacy by becoming a two-weight world champion,” Jacobs said. “There are some great fighters and champions at 168 pounds and I believe that I will be a different beast up at super middleweight. Facing Julio is a great test for my first fight. He’s a former middleweight champion like me and he has the same goal as I do. I am sure that our styles will gel to be a thriller for the fans, and I plan to announce my arrival at 168 pounds in style.”

Chavez’s participation in the bout comes with some controversy. He was temporarily suspended by the Nevada State Athletic Commission for declining to submit to a random Voluntary Anti-Doping Association drug test, but that is not expected to impact the bout because, according to Hearn, the Arizona Boxing Commission has already issued a license to Chavez.

Jacobs-Chavez was originally ticketed to take place at the MGM Grand Garden Arena in Las Vegas. When Hearn requested the date for the bout, the Nevada commission, as per its rules, elected to activate its enhanced drug testing protocol, with VADA handling the collection.

Chavez has twice failed tests for banned substances in Las Vegas, which was a key reason the commission activated its enhanced drug testing. But Chavez refused to be tested when a collection agent showed up seeking a sample at the Wild Card Boxing Club in Hollywood, California, where Chavez was training, and he was suspended.

Chavez had not yet signed for the bout, however, at the time the tester arrived. Chavez is supposed to have a hearing on the issue before the Nevada commission on Nov. 20.

Hearn said he put a hold on the MGM Grand but also was looking at two other possible sites for the bout, one in Texas and Phoenix. Once Chavez was suspended by Nevada, Hearn told ESPN that he spoke to the Association of Boxing Commissions for its take. He said the organization said Chavez was free to pursue a license in any other state.

Hearn said after the testing issue and Nevada suspension, he knew he would not be able to stage the fight in Las Vegas.

“Obviously, we couldn’t go there, so we checked with the ABC and with Arizona, which gave us a list of requirements,” Hearn said. “One was for testing from when the fight is signed. I’ve never seen anyone sign up for testing as quickly as Chavez did. Arizona said that as long there is testing from when the contracts are signed, we are fine to have the fight there.”

Should there be any issue, Hearn has Philadelphia’s Gabriel Rosado (24-12-1, 14 KOs), 33, a former two-time middleweight world title challenger, scheduled to fight on the undercard and on standby to step in to face Jacobs if necessary.

Since losing a shutout decision to Alvarez in May 2017 in a fight in which Chavez was roundly criticized for a lack of effort, he has only fought once. He notched a first-round knockout against journeyman Evert Bravo on Aug. 10 in Mexico and said he is highly motivated to face Jacobs.

“Going against Daniel Jacobs is the perfect fight for me because there is so much on the line,” Chavez said. “A victory gets me one step closer to a world championship and I’m not going to let anyone stand in my way.

“I know that Danny Jacobs is a former world champion and is a strong fighter with very good boxing skills. Those are the kind of boxers that bring out the best in me. I’ve been working hard in the gym and can’t wait to let everyone see what I’ve been working on. I’m very motivated to get the win and at the end of the night I will have my hand raised in victory. I ask my fans to believe in me. I will deliver.”

Although the undercard has not been formally announced, Hearn told ESPN about two bouts that will be on the card:

Flyweight Julio Cesar Martinez will face Cristofer Rosales for a vacant world title. Mexico’s Martinez (14-1, 11 KOs), 24, who recently signed with Hearn, challenged Charlie Edwards for flyweight belt on Aug. 31 in London and dominated. The fight was initially ruled a third-round knockout win for Martinez but changed to a no contest minutes later because Martinez landed a punch while Edwards was down. Rather than fight Martinez in a mandated rematch, Edwards elected to vacate the title and move up in weight. So Martinez was ordered to face Rosales for the vacant belt.

Rosales (29-4, 20 KOs), 25, of Nicaragua, won the title by ninth-round knockout of Daigo Higa on his turf in Japan in April 2018 and made one successful defense before losing it by unanimous decision to Edwards last December. Rosales has won his only fight since.

Former junior welterweight world titlist Maurice Hooker (26-1-3, 17 KOs), 30, of Dallas, who lost his belt by sixth-round knockout to Jose Ramirez in their July 27 unification bout, will face Pedro Campa (31-1-1, 21 KOs) at a contract weight of 144 pounds. Hooker will be in his first with new trainer Brian McIntyre after parting ways with career-long trainer Vince Parra following the loss to Ramirez.