Joshua is next expected to defend his IBF, WBA and WBO heavyweight titles on April 13 at Wembley Stadium.
Deontay Wilder, the WBC champion, is the preferred opponent with Hearn saying earlier this week: “Anthony Joshua has 75 per cent of the belts, but we want that 25 per cent.”
Wilder also has the option to rematch Tyson Fury, with whom he drew earlier this month. That rematch would open the door for another challenger to Joshua.
Undisputed cruiserweight champion Usyk’s intention to face Joshua in the top division has long been clear, but is not likely to happen next.
“I saw reports saying that the Joshua fight was done. Certainly not,” Hearn told Sky Sports. “There’s not even been one conversation about that fight, other than they want it in the future. But if he’s going to move to heavyweight, there’s nothing concrete yet.”
Usyk knocked out Tony Bellew last month, and now holds all four major cruiserweight belts as well as a gold medal from the 2012 Olympics and the World Boxing Super Series trophy.
His promotional company K2 Promotions are working alongside Matchroom for Usyk, and he will attend next week’s Sky Sports Box Office clash between Dillian Whyte and Derek Chisora.
Asked if Usyk’s future would be discussed when he arrives in London, Hearn said: “Yes, he’s going to need a good rest because he boxed so many times last year. He hardly had any rest between big fights, so I don’t think he’ll be ready until April or May.
“I would think he’ll want one or two fights before he fights Joshua.
“But if he would take that fight straight away, and Whyte or Chisora are not available, and we can’t make Wilder or Fury, I don’t know.
“But [Joshua vs Usyk] is not something we’re actually looking at, at the moment.”
Usyk’s manager Egis Klimas said last month: “We won’t be going for Joshua in the first fight [at heavyweight]. He will need a fight or two against the bigger guys. But he will be a very, very good heavyweight. He will bring his speed and he has shown he has the power.”
Whyte could issue a reminder of his credentials to challenge Joshua on April 13 if he beats Chisora next week.