Now that Parker has defended his title in a mandatory challenge, he is free to fight a voluntary against an opponent of his choice.
There are several options - a unification fight against one of the other title holders would in theory be desirable, but that is unlikely to happenin the short term.
Parker remains on a collision course with WBA, IBO and IBF title holder Anthony Joshua, but that fight will probably be allowed to build in order to increase anticipation.
Kyotaro Fujimoto (Japan): Parker's promoter David Higgins likes the idea of fighting Fujimoto, who is ranked No9 with the WBO because the 31-year-old has a 17-1 professional record and would be considered a relatively easy night in the ring. Even more alluring is the fact that Japan have never had a heavyweight challenge for a world title and that could create interest there, which equals views and revenue.
Dillian Whyte. Photo / Getty Images
Dillian Whyte (England): Whyte has been quick to challenge Parker and a fight against him makes good sense for Parker. Whyte, 29, nicknamed 'the Body Snatcher' as a 21-1 record and is ranked at No10 by the WBO but in reality is at several levels below as an elite heavyweight. Crucially, Whyte has a relatively high profile in the UK.
Deontay Wilder. Photo / AP
Deontay Wilder (USA): The Bronze Bomber is the WBC champion with an extraordinary record of 38-0 record, including 37 knockouts. He is fighting Luis Ortiz in a title defence in November which would make him a very unlikely opponent for Parker next up, but he's one that Parker's camp will be eager to get in the ring with. Wilder is a wild, unorthodox puncher but has never truly been tested.