Joshua, 32, will lock horns with the undefeated Ukrainian for the second time in a rematch next month on August 20, which will take place at the Superdome in Jeddah, Saudi Arabia.
The victor of the contest will be crowned the unified heavyweight world champion and could set up an undisputed fight with current fellow WBC and Ring magazine titleholder Tyson Fury.
Ruiz Jr has shared the ring with Joshua before, having shocked the world by beating the Brit in June 2019 before losing the belts in a rematch a few months later, and is all too well aware of his strengths and weaknesses.
The Destroyer, like many others, believes it will all comes down to who hits the hardest, a department he reckons Joshua has a slight advantage in.
“I think he [Joshua] can [win], you know, in the heavyweight division, anything could happen,” Ruiz Jr told Fight Hub TV.
“It only takes one punch to change the fight. So, it’s all up to the one that’s more hungry.
“Anthony Joshua goes down and he comes back up or he loses, and then he fights again to win.
“Usyk is a hard guy too. You know, his style. He throws combinations.”
Ruiz Jr, also 32, will also be back in action later this year, locking horns with Cuban veteran Luis Ortiz on September 4 at Los Angeles’ iconic Crypto.com Arena.
The Mexican has not fought since a unanimous decision win over Chris Arreola in California in May of last year.
He added: “Hopefully if I win on September 4 against Luis Ortiz, if Joshua doesn’t win then we could look for Usyk if he wins.
“The heavyweight division is so open right now. I just got to get this win first against Luis Ortiz. Like I said, it’s a hard opponent, but, of course, I would love to fight Wilder if he comes out of retirement.
“I don’t know if he said he’s going to come out of retirement, but I would love to fight him. We’re both under PBC and Al Haymon, and that fight would be easy to make.”