Speaking to The Daily Telegraph, Panther's Head of Performance Hayden Knowles says the halfback has transformed his figure over the break to help the Penrith outfit go deeper into the finals and potentially take home honours at the big dance.
"Last year he played around 88kg, Nath has now put on another four kilos," Knowles Said.
“Importantly, he’s also faster and more powerful, too. So it’s not like we’re trying to make a body builder of him; it’s both upper and lower body strength where he’s improved.”
Knowles also admits that Cleary's new engine is down to the extra work he's been putting in.
“Everything Nathan Cleary does is with total commitment,” he continued.
“And that’s how it has been again this off season.
“He’s last guy out of the gym, last guy off the field and last guy to leave our academy every night.
“When everyone else has gone home, Nathan is still here studying video. It’s a commitment he brings to everything he does."
With his best years ahead of him, Knowles thinks Cleary has all the traits and the work ethic to become a standout player in the NRL and he's now entering the best years of his career.
“It’s why you’ll hear stories about footballers like Cooper Cronk and how they prepare at the back end of their careers, just as you’ll hear it about basketballers, golfers, cricketers and so on.
“And one day they’ll be telling Nathan Cleary stories, too. Only it will be how he was doing all that from the age of 22.”
It's harsh to judge a player while they're still young - It can take a few seasons to become accustomed to the step up in physicality while most athletes take several years before they start to come into their own. In his early 22s, Cleary is now reaping the benefits of having a few off-seasons under his belt.
“So you could credit the strength coaches, the nutritionists, even the Oak Milk,” Knowles added.
“But as Nathan Cleary gets older, he’s going to develop more, too.
“That’s why he’s going to be stronger again next year. And stronger again the year after that.
“Like with Olympic athletes, the statistics show they don’t peak until their late 20s.”