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.