NEW YORK -- Though many have assumed that Anthony Joshua would insist that his rematch with Andy Ruiz take place on his turf in the United Kingdom, the former unified heavyweight world titlist is seriously considering fighting Ruiz again at Madison Square Garden, Matchroom Boxing promoter Eddie Hearn told ESPN on Saturday.

Joshua, a megastar in the U.K., made his United States debut on June 1 at the sold-out Garden and lost his three world title belts to Ruiz via monumental upset. Joshua dropped Ruiz in the third round but suffered two knockdowns later in the round, and two more in the seventh round, before the fight was stopped, marking one of the biggest shockers in boxing history.

On Wednesday, Joshua exercised his right to an immediate rematch. Because the Joshua side controls the logistics of the bout, including the site, it was assumed it would be in the U.K. -- especially because after the bout, Hearn said it would be there, likely in November.

But it won't necessarily take place in the U.K., Hearn said on Saturday.

"[American broadcast partner] DAZN would prefer it in the U.S. They'd still cover it in the U.K., of course. [British broadcaster] Sky would prefer it in the U.K.," said Hearn, who turned 40 on Saturday. "For me, I want to win the fight, so there is an edge to doing the fight in the U.K., unquestionably. But AJ is like, 'Do you not think I should go back to where it went wrong and put it right?' I said, 'That's an incredible attitude to have, but we need to win the fight.'

"He said, 'I almost feel like it's a cop-out making Ruiz come to my backyard. He's the champion. It will be more spectacular if I beat him [at Madison Square Garden].' I'm like, 'I agree, but...' That's the conversations at the moment. He's thinking if he put it right there it would [be] even more spectacular than if he put it right in the U.K."

Hearn said if the fight takes place in the U.K., it likely would be at Principality Stadium in Cardiff, Wales, where Joshua (22-1, 21 KOs), 29, has drawn sold-out crowds of about 80,000. The reason to do the fight there is because having it outdoors at Wembley Stadium in London, where Joshua has drawn 90,000, is dicey because of the weather in November.

Ruiz (33-1, 22 KOs), 29, of Imperial, California, is the first fighter of Mexican descent to win a heavyweight world title. He said after the fight that he'd prefer for a rematch to be in the U.S., but Ruiz also said he'd have no problem going to the U.K. for the rematch, whose terms were outlined in the contract for the first fight.

Hearn said if the fight is in the U.S., they only want to have it back at Madison Square Garden.

"It's not a case of AJ saying, 'Bring the rematch back to the States.' It's a case of him saying, 'Do it where it went wrong, in that exact ring,'" Hearn said. "He's like, 'If I'm going to put these demons to bed, I will never do that until I box there again.'"

Joshua, who suffered a concussion in the fight, most likely from the left hook to the temple area that knocked him down for the first time in the third round, remained in New York until flying back to England on Friday.

"He doesn't remember a whole lot after the third round," Hearn said. "He said, 'How I lasted four rounds after that I don't even know. I didn't remember where I was.'"

Hearn said Joshua was "devastated" by the shocking loss, even though he smiled his way through his postfight news conference and gave Ruiz ample credit for the victory.

"He's still devastated, but he was putting on a brave face. He didn't leave the house [he was renting in New York's West Village] all week," Hearn said. "He wasn't sleeping, and I said to him, 'You've got to use this pain that you're feeling to motivate you.' I know how much of a competitor he is. He's like, 'I know I boxed terribly. I know how to beat him, and I'm going to put it right.'"

Hearn also brushed off rumors that Joshua had been hurt in sparring in the later stages of his Miami training camp by Philadelphia heavyweight Joey Dawejko and that Joshua had a panic attack in the dressing room before walking to the ring.

"Rubbish," Hearn said. "We need to start giving Ruiz the credit. There was nothing wrong with Joshua. He was 100 percent, he had a great camp, there was no panic attack in the dressing room. The only thing that happened in the dressing room was he had to change his groin protector at the last minute because the one he was wearing was riding up and uncomfortable when he was warming up. So he changed it, and that was that."