Chazz Witherspoon was reluctant at first to discuss whether Andy Ruiz Jr. or Anthony Joshua would represent a greater challenge for Oleksandr Usyk.

“I don’t know,” Witherspoon told BoxingScene.com after his technical-knockout defeat to Usyk on Saturday night in Chicago. “I don’t like making predictions on people. But I don’t know. We’ll see. It depends on who wins that fight. I think that definitely matters, who wins that fight, who he’ll fare better against. You know what I mean?”

Ukraine’s Usyk (17-0, 13 KOs) is guaranteed a shot at the WBO heavyweight championship Ruiz won from Joshua on June 1 at Madison Square Garden in New York. The former undisputed cruiserweight champion is the WBO’s mandatory challenger for whomever wins the immediate rematch between Ruiz (33-1, 22 KOs) and Joshua (22-1, 21 KOs) on December 7 in Diriyah, Saudi Arabia.

England’s Joshua is a 3-1 favorite to avenge his seventh-round TKO loss to Ruiz when they square off again for Ruiz’s IBF, IBO, WBA and WBO crowns.

Witherspoon wouldn’t predict whether Ruiz or Joshua will win that bout. The Philadelphia native did eventually elaborate on how the 32-year-old Usyk would fare against each of those heavyweights.

“Ruiz can rumble, so I don’t wanna say nothing [negative] about him, because he can rumble,” Witherspoon said. “And if he cracks you, he moves his hands, he’s good. But I think Usyk is bigger, longer. I think he out-points Ruiz. Now Joshua, that’s a whole other animal because Joshua’s so big and so strong. And yeah, that one, I think that would be the tougher fight for Usyk.”

The 6-feet-3, 215-pound Usyk would face a significant size disadvantage against the 6-feet-6, 245-pound Joshua. At 6-feet-2, Ruiz is slightly shorter than Usyk, yet the Imperial, California, native would out-weigh Usyk by even more than Joshua.

His thoughts on how Usyk matches up with Ruiz and Joshua aside, Witherspoon was impressed with Usyk in the 2012 Olympic heavyweight gold medalist’s debut as a full-fledged heavyweight. Usyk was busier and better throughout their bout until Tommy Brooks, Witherspoon’s trainer, told referee Hector Afu to stop their scheduled 12-rounder after a one-sided seventh round.

Witherspoon (38-4, 29 KOs) believes Usyk’s skill set will enable him to fare well against any heavyweight he encounters.

“Like they always said, his footwork, he can change gears, he’s fast, awkward,” Witherspoon said. “That awkwardness can always throw you off. You’ve gotta prepare for that. So, he’s elusive, and he kinda knows what he’s doing in there. And it’s not like he gets flustered. It’s not like he ever got really flustered. So, he keeps his composure. He’s a true professional.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.