The WBA (Super), IBF, WBO, and IBO title holder is set to take on IBF mandatory challenger Kubrat Pulev in London in November, after which he has already agreed on a two-fight deal with Tyson Fury.
Fury is due to face Deontay Wilder in the final fight of their trilogy later this year, after which he has been ordered to fight WBC mandatory challenger Dillian Whyte, provided he beats Alexander Povetkin this weekend.
Should the 32-year-old fail to take on that bout, promoter Hearn has predicted the belt to go on the line in a meeting between Joshua and his former rival Whyte.
“Looking at the bigger undisputed picture, all Joshua wants is the WBC title,” Hearn told Sky Sports News.
“He was never worried if it came against Wilder or Fury. Whoever!
“Whoever owns that belt is who Joshua will face for the undisputed championship.
“We know the winner of Saturday’s fight will be ordered to face the winner of Fury vs Wilder.
“If Fury does not want to fight Whyte, then Whyte will be elevated to champion from interim champion. Now I do not like that.
“But what will happen? Joshua will fight Whyte straight away for the undisputed championship.
“You always want to fight a champion. But if Fury refuses to do a fight that has been ordered by the WBC, then he will be stripped of his title.
“Then Whyte will be fighting for the undisputed championship.
“Whyte has had the bad end of the stick for a long time but could end up, if he’s successful, fighting Joshua for the undisputed championship. So this is massive for him.”
Whyte has won 11 fights since his solitary defeat to Joshua in 2015, and has been desperate for a title shot for some time.
The 32-year-old said earlier this year: “I’ve waited long enough now and I’ve been mandatory and number one for long enough now. The WBC have got to uphold their end of their bargain.”