As Jon Jones prepares to make his step-up from light heavyweight later this year, UFC rival Daniel Cormier has raised doubts over the Rochester fighter's knockout credibility.

Since his debut at UFC 87 in 2008, Jones, 33, has become one of the biggest names in the sport, but there remain questions over his status as perhaps the greatest fighter ever.

Not least due to a number of doping violations, and a third suspension, where Jones was cited for his involvement in a hit-and-run incident during 2015.

After a bitter dispute with UFC head Dana White last May, Jones opted to relinquish his Light Heavyweight crown, with a move up to heavyweight touted.

That now appears to have come full circle, and Jones looks to be making huge progress in training.

Indeed, should Jones be successful at heavyweight, he can become part of an exclusive club of two-weight champions in UFC.

But former rival and now retired Cormier believes the man that controversially beat him four years ago, may not have the pedigree and power to make it at the top weight.

During his latest YouTube show with journalist Ariel Helwani, Cormier, himself a two-division champ, believes Jones will struggle to knock out the bigger men in UFC.

“Jon Jones will not knockout anyone at heavyweight. He doesn’t hit hard enough. If he couldn’t knock these dudes out at 205-pounds, he’s not knocking these heavyweights out.

"It doesn’t matter if you put on weight, it still takes punching power. Why do you think Derrick Lewis can lose 30lbs, see how much leaner he is, and still knock people out? It takes power, it’s not just weight. There’s people at heavyweight who can’t knock people out."

During Jones' first suspension, it was Cormier who took the place of Jones against Anthony Johnson, who himself went on to claim the vacated Light Heavyweight Championship.

Both Jones and Cormier have met twice in the Octagon, most recently at UFC in Anaheim, where Jones took the belt from Cormier in their rematch from 2015, via a third round KO.

Subsequently however, it was revealed the former has tested positive for Turinabol, a banned anabolic steroid, and the decision was taken by the California State Athletic Commission to rule the fight a no-contest, returning the title to Cormier.

Cormier and Jones will obviously never be friends after their storied past, but that hasn't stopped the YouTube host getting his shot in once more, and says he can state from experience, that his former foe does not punch hard enough for a heavyweight.

“I’m telling you from experience, Jones doesn’t punch very hard. Kicks very hard. Knees very hard, but his punches… that’s going to be an issue for him once he faces the heavyweights because they know.

"They know he wasn’t knocking those guys out at 205 so they’re going to be more willing to walk him down.”

Whether Cormier's claims hold any credence, all eyes will undoubtedly be on Jones when he makes his heavyweight bow, later in the year.