Junior lightweight world titleholder Gervonta "Tank" Davis could be back in the ring as soon as April - but not for an official fight.
Ruiz was a late replacement for three-division champion Abner Mares, who withdrew from the bout two weeks ago with a detached retina in his right eye.
'But he has an exhibition bout with Tenshin (Nasukawa) in Japan in April.
Gervonta Davis retained his World Boxing Association super featherweight world title with a vicious first-round knockout of former world champion Hugo Ruiz on Sunday.
According to Mayweather, Davis' next challenge will pit him against Japanese kickboxing ace Tenshin Nasukawa in April.
Floyd Mayweather has confirmed he's organised Tenshin Nasukawa's next fight and it's another "exhibition".More news: Ministers indicate new chance to vote on May's Brexit deal
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"I'm proud of Tank, and he's gonna stay active", Mayweather said. He is fighting Tenshin in an exhibition match in Japan, in RIZIN.
The 24-year-old Davis is the youngest US -born world titlist in boxing and was headlining for the first time.
On New Years Eve, Mayweather returned to the ring by facing Nasukawa in a three-round exhibition but it didn't last long.
Mayweather Promotions has plans to bring Davis home to Baltimore for a summer title defense, but Mayweather did not mention where specifically the May fight would take place or against whom.
It was a 12th straight win by knockout for American Davis and his 20th win inside the distance from 21 fights.
By the end of the fight, Nasukawa was reduced to tears, such was the onslaught that he faced at the hands of his rival.