Matchroom Boxing announced the multi-fight deal with a social media post on Wednesday.

The Ring’s Mike Coppinger reported that Ruiz is in discussions to face Damian Knyba on Sept. 4 in Newark, New Jersey. That bout will be paired with a middleweight clash between Austin “Ammo” Williams and Vito Mielnicki Jr.

“I had to be broken to be reborn,” Ruiz said in a video Matchroom shared to announce his signing.

“I feel right now I’m more strong mentally and physically and I’m more hungry. I’m better than a lot of these other heavyweights that are out there right now. All the belts that everybody has, I want them. I want them back. I'm motivated, and I'm hungry from all the stuff that I've been through.”

Ruiz became the first heavyweight champion of Mexican descent with one of boxing’s biggest upsets this century, stopping then-unified and undefeated titleholder Anthony Joshua in June 2019 at New York's Madison Square Garden. The Imperial, California, native lost by unanimous decision in the rematch six months later in Saudi Arabia.

Inactivity has marred the 36-year-old's career since his two-fight series with Joshua.

He has only fought three times, notching decision victories over Chris Arreola in 2021 and Luis Ortiz in 2022. Ruiz (35-2-1, 22 KOs) most recently boxed to a controversial majority draw against Jarrell Miller in August 2024.

Knyba (17-1, 11 KOs), of Bydgoszcz, Poland, is coming off a third-round stoppage defeat to recently upgraded WBC heavyweight champion Agit Kabayel in January. The 6-foot-7 heavyweight has fought much of his career in New York and New Jersey, where he currently resides.