Matchroom chairman Barry Hearn has made Bermane Stiverne his No 1 choice to fight Anthony Joshua next.
IBF heavyweight champion Joshua (17-0-KO17) has won his first two world title fights against Charles Martin and Dominic Breazeale this year and is mandated to begin negotiating a defence against Joseph Parker by November 9.
But there might be room in Joshua's schedule for a voluntary defence against ex-WBC holder Stiverne (25-2-1-KO21), Hearn believes.
He exclusively told Sky Sports: "Parker may well be next but I suspect, probably, Joshua will have another defence prior.
"There's a whole range of names out there - whether you're talking Stiverne, Eric Molina.
"Stiverne is probably my No 1 choice because of his credibility."
Hearn has also goaded Hughie Fury (20-0-KO10) to step into the ring against Joshua, who has spoken of his willingness to take on the 21-year-old and his cousin Tyson Fury, the WBA 'Super' and WBO champion.
He said: "I'd like to see Hughie Fury step up and have a go! They're two undefeated fighters and it's a fight that would sell to the British public.
"There's a lot of choice - it's a lot easier when you're the champion than the challenger."