Andy Ruiz Jr is in incredible shape for his return to professional boxing this weekend.

The American-Mexican bruiser will step between the ropes for the first time since his comprehensive points loss to Anthony Joshua in December 2019 when he slugs it out with Chris Arreola.

Much has been made of the physical conditioning of Ruiz Jr after the former unified heavyweight champion admitted to piling on too much weight for his second bout with Joshua.

Ruiz Jr's weight gain for AJ rematch

According to the Independent, just moments after judges revealed that he had lost the WBO, WBA and IBF heavyweight titles in Saudi Arabia, Ruiz Jr openly remarked: "It was his night man.

“I think I didn’t prepare as how I should have, I gained too much weight. I don’t want to give excuses but I gained too much weight.”

Now, it goes without saying that you shouldn't judge a book by its cover when it comes to people's bodies and those less familiar with Ruiz Jr often raise their eyebrows when they see his physique.

Back to business

However, by all accounts, Ruiz Jr wasn't in his optimal shape for the 'Clash on the Dunes' and has sought to improve his conditioning under the watchful eye of new coach Eddy Reynoso.

Fight fans might have expected to see Ruiz Jr back in action sooner than 2021, but it's clear that the 31-year-old has been putting in the work to ensure he gets back to winning ways against Arreola.

And after a series of training photos hinted that Ruiz Jr had been shedding the pounds since the Joshua defeat, the full extent of his body transformation was confirmed upon the official weigh-in.

Ruiz Jr completes body transformation

That's because, according to talkSPORT's Michael Benson, the former world champion weighed in almost two stone lighter than he did for the Joshua rematch in Diriyah.

While the Ruiz Jr that was outboxed by Joshua weight in at 283 pounds, his new and improved self tipped the scales at 256 pounds and the difference in his physique was clear for everyone to see.

Exact side-to-side comparisons are hard to create when Ruiz Jr kept his t-shirt on at the weigh-in for the Joshua rematch, but images from the fight are still incredibly illustrative, so check them out:

You've got to credit Ruiz Jr for addressing something that he clearly felt held him back in Saudi Arabia.

Andy Ruiz Jr vs Chris Arreola

Besides, there's no denying that Ruiz Jr didn't look like the fighter who bulldozed Joshua at Madison Square Garden just a few months prior, barely winning two rounds in his mission to defend the belts.

But now that he's changing his tact under Reynoso's wing, you can certainly expect Ruiz Jr to throw a cat amongst the heavyweight pigeons when he surely smashes his way past Arreola.

For all the American's durability, it's doubtful that he'll stand a chance against a trimmer and sharper Ruiz Jr who we hope to see up against the best heavyweights in the business very soon.