The Mexican Destroyer will be back for the first time since he lost to Anthony Joshua in December 2019.
Ruiz will now face Chris Arreola in his first fight at Dignity Health Sports Park, in California.
The Mexican fighter is now leaner than ever for the fight after losing nearly two stone of weight (26lbs).
When he lost his heavyweight titles back to Anthony Joshua in Saudi Arabia, Ruiz had weighed 283lbs.
But Ruiz is now at 257lbs and wants to be at 255lbs.
He has continued training in California, with coach Eddy Reynoso and everyone can see the results.