Anthony Joshua was due to face ‘Big Baby’ Miller in New York’s Madison Square Garden on June 1.
But the Brit is looking for a new challenger for his Stateside debut after Miller was denied a licence to fight following three failed drug tests.
Joshua’s promoter Eddie Hearn, of Matchroom Boxing, has been hard at work lining up a replacement with Mexican Ruiz having been billed as a fresh alternative.
Luis Ortiz has removed himself from the pecking order while ESPN claim that Michael Hunter, Manuel Charr, Trevor Bryan and Agit Kabayel are the other possible options.
Ruiz, who is 32-1, fought Joseph Parker for the WBO belt three years ago with a loss to the New Zealander the only blotch on his record.
But the California-raised heavyweight felt he actually won that fight, which he lost by majority decision, and has claimed on Instagram this week he is ready to step up and prove himself by facing Joshua.
And speaking earlier this month, before his fifth-round knockout of Ukrainian-born journeyman Alexander Dimitrenko, Ruiz insists he would be better of taking on Joshua than the division’s other two stand-out names, Deontay Wilder or Tyson Fury.
He told reporters: “If I were to pick AJ, Wilder or Fury, I think I would pick AJ. All three of them would be a blessing to fight for the opportunity of a world title, you know.
“But I think in my eyes, AJ would be an easier opponent how his style is. Him and Parker went the distance as well.
“Either one of those I’d love to fight. The style, the money, style makes fights and I think with his style it would be a better style for me [to face AJ].”
On what he has to put himself in contention to challenge the trio, Ruiz added: “First I’ve got to get back on track and get these fights in and then I’ll be ready for a world title. Just win fights, I’ve got to win fights.
“The people that they bring in front of you, you’ve got to win and win spectacular. That’s what I’ve got to do.”
Joshua, Wilder and Fury are all signed to different networks but Ruiz insists that wouldn’t matter if he was to share the ring with any of the triumvirate.
“Yeah but if the fight’s right, the money’s right, our networks will work together,” he continued.
“The main thing is to stay focused, stay disciplined, keep winning fights and I’m pretty sure I’m going to get that world title shot.”
Joshua confirmed in a video on his YouTube channel on Monday night that his next opponent is to be announced in the coming days with Hearn having been meeting with several of the fighters lined up as possible replacements this week.