Five years must pass from retirement until a fighter enter's boxing's Hall of Fame.
The Ukrainian great hung up his gloves after a glittering 21-year professional career which culminated in arguably his greatest fight, if not result, back in April, as Joshua climbed from the canvas to best the 41-year-old in a pulsating Wembley scrap. He dominated the heavyweight division for over a decade.
Freddie Cunningham of AJ Boxing added: "The two dates have always been discussed, and are still both in play". I think fight fans are going to see an announcement sooner than they would have with a Klitschko fight.
Wladimir Klitschko was popular in Germany, where he staged several massive outdoor-stadium title defenses.
Boxer Wladimir Klitschko has announced his retirement from the sport in a statement provided on his website.
'According to the resolution sent on January 11th, 2017, to both parties, it was reported that the victor of the Joshua-Klitschko fight, held on April 29th, 2017, had to face Ortiz after 120 days, ' a WBA statement read.
The brothers never fought each other, saying that would break a promise to their mother.
"I was, and am still capable of, doing all this because of the global appeal of the sport of boxing, my own talent, and most importantly because of you, my loyal fans".
Klitschko himself admitted before his final fight that he had been boring even while beating everyone who was put in front of him.
This time around Klitschko took the decision out of the judges' hands and produced a dominant performance to stop Byrd in the ninth round, becoming a two-time heavyweight champion. The Englishman came back from the brink to win a thrilling contest with the Ukrainian earlier in the year, getting off the floor to eventually stop Klitschko in the 11th round.
Katie Taylor's team are looking at Las Vegas in November for her much anticipated world title bid.
Hearn knows he's unlikely to gain a second exception from the IBF who already gave special dispensation for Joshua to defend his red belt against Klitsckho.
There's no reason to risk taking a beating in a rematch with Joshua.
Klitschko followed his older brother Vitali into boxing after winning Olympic gold in Atlanta.
That has only intensified with Parker getting hold of one of the four coveted belts and a determination from the current champions - American Deontay Wilder holds the WBC title - to try to unify the the titles.
He's also leaving with two straight losses, after losing his titles to Tyson Fury in 2015 and being stopped by Joshua.