UFC light heavyweight champion Jon Jones is having his doubts that new undisputed UFC middleweight champion Israel Adesanya is serious about moving up to fight him.

Though Jones and Adesanya have been talking up a potential matchup in recent months and UFC president Dana White has even discussed the possibility of booking the two for a fight, Adesanya’s win over Robert Whittaker on Saturday at UFC 243 apparently did little to convince Jones that “The Last Stylebender” is truly ready for the challenge.

“By the time this kid gets his confidence together I’ll probably already be in the heavyweight division. I don’t need to wait till 2021 to start believing in myself,” Jones wrote, replying to a comment from UFC heavyweight contender Francis Ngannou.

The 2021 date is in reference to Adesanya recently telling the media that he would like to have a strong middleweight championship run before pursuing the Jones fight.

Jones has long suggested that he’ll eventually transition from light heavyweight to heavyweight, though he’s yet to make any serious overtures outside of a stirring up a rumor in July that he might fight Stipe Miocic. In 2019, Jones has competed twice, successfully defending his 205-pound championship against Thiago Santos and Anthony Smith.