Gilberto Ramirez has expressed interest in fighting Callum Smith in the UK to unify the super-middleweight division.
The unbeaten world champions met this week in California's Wild Card gym and now their promoters have begun talks over a fight.
"Smith is the standout No 1 super-middleweight in the world, and Ramirez is No 2," promoter Eddie Hearn told Sky Sports.
"[Ramirez's promoter Bob Arum] tells me that they are up for coming to the UK for that fight. With all the debate about big fights going to the States, this is a genuine front-runner for the No 1 fight in a division to land in the UK.
"I'm excited to try and make that happen."
Smith is 25-0 and holds the WBA title after winning the World Boxing Super Series. Ramirez, 39-0, holds the WBO belt but will make his debut as a light-heavyweight this weekend against Tommy Karpency.
Arum told Sky Sports: "[Ramirez] talked to me about going into the light-heavyweight division but before I put him in with the killers - Sergey Kovalev, Artur Beterbiev - I wanted him to test himself with Karpency. He is doing that. Then, it's up to him whether he stays at 168lbs or goes to 175lbs.
"I think he is intrigued by fighting the Englishman, and even coming over to England. Eddie Hearn assures me it would be a massive fight."
Hearn added: "Bob Arum is one of those few guys in boxing who could say anything about, but an hour later he picks up the phone to close a deal. That's great news.
"He doesn't let his ego get in the way, or his emotion get in the way, of making a deal.
"I know, because he told me, that he's up for Ramirez vs Smith. It's a great fight, the best fight in the division."
Smith has become a father since the standout victory of his career over George Groves, but plans to next fight on the Anthony Joshua vs Jarrell Miller undercard on June 1, live on Sky Sports Box Office.
"It will be a world title defence - we're speaking to a lot of guys in the ranking," Hearn said.
"The division is quite thin, there isn't much depth in terms of big-name contenders.
"We want to see him look explosive then set up a big unification fight."
John Ryder will battle David Lemieux on the Saul 'Canelo' Alvarez vs Danny Jacobs undercard on May 4, live on Sky Sports, and the winner will become mandatory to Smith's WBA title.
"It's a 50-50 fight," Hearn said about Ryder vs Lemieux.
"Lemieux is a good fighter. You saw what Billy Joe Saunders did to him, but Billy Joe is extremely skilful. So is John, but John likes to have more of a fight than Billy Joe which is dangerous because Lemieux is heavy-handed."
The IBF super-middleweight champion is Caleb Plant and the WBC title is vacant.
Vasyl Lomachenko defends the WBA and WBO lightweight titles against Anthony Crolla on Saturday morning at 3am, live on Sky Sports Main Event and Sky Sports Action.