Eddie Hearn has added Kubrat Pulev and Joseph Parker to the list of heavyweights Anthony Joshua could fight before the end of the year.
Bermane Stiverne has told Sky Sports he is already in training camp for a possible tilt at Joshua's IBF heavyweight title but promoter Hearn revealed there are others in the mix.
We are putting the feelers out over the next few weeks to secure the next move.
Joshua is mandated to face New Zealand's Parker by the end of January but could take the fight beforehand, while Bulgarian Pulev - who outpointed Dereck Chisora to become European champion in May - is a new name on the shortlist.
"I let the old man [Barry Hearn] reach out to Don King last night and they discussed old times and also the possibility of Joshua v Stiverne for November," Hearn told Sky Sports.
"He is definitely an option and a great fight for Joshua. Although the mandatory isn't due next we may look to go straight into Joseph Parker and I have also discussed the possibility of Pulev with Kalle Sauerland.
"We are putting the feelers out over the next few weeks to secure the next move."
Stiverne has been labelled as "durable" by Joshua and was only beaten on points when he lost his WBC world title to Deontay Wilder, whose other 35 victims failed to hear the final bell.
Parker (19-0-KO16) has impressed in securing the IBF mandatory position, stepping up in class to outpoint Carlos Takam in May, and is scheduled to fight Solomon Haumono in Christchurch on July 21.
Pulev's only defeat in 24 contests was in November 2014 when he was stopped inside five rounds by Wladimir Klitschko when he was challenging for the IBF belt now belonging to Joshua.