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At 6'2" and 226 pounds, there are few physical hurdles Jarryd Hayne stumbles over.

He showed that repeatedly during his years of dominance in Australia's National Rugby League, where the "Hayne Plane" took off. He twice earned the Dally M Medal, the league's player of the year award, and generally spent his time punishing opponents, then running far, far away.

If you're not familiar with his bruising style, go ahead and clear your schedule for 11 minutes.

Hayne's imposing physical strength is what opened NFL eyes when the 27-year-old expressed an interest in making the transition to American football—or, as it's commonly called in Australia, gridiron football.

Now with the San Francisco 49ers and trying to make the roster as either a running back or kick returner (both?), Hayne showed impressive vision to identify and bolt through a lane on only his second career touch, rumbling for a 53-yard gain against the Houston Texans.

An American audience meeting him for the first time was left to ask a simple question: Who is this guy?

Hayne was asking a different question back in March after signing with the 49ers: What is king-right-trips-iso-three-on-two?

He could hammer through any physical challenge, but the steep mental climb of learning an NFL playbook had just begun, as he told Australian radio host Alan Jones in March (via Fox Sports):

Some of the play calls are pretty tough. This is just one play call I think: it's king-right-trips-iso-three-on-two. And then if (the quarterback) gets the defence that he thinks knows the play, he'll go 'Kill! Kill!' and then change the play at the line of scrimmage. Then I've got to know the kill play as well. With the crowd noise and all that sort of stuff, I've got a long journey ahead.

What Hayne described there seems routine to anyone who's played football even at a high school level. You master the playbook, along with the seemingly endless variations on each play and possible audibles.

But when you're a thriving, immensely successful athlete in one sport and then attempt to make the transition to the absolute highest level of another sport, nothing is easy or simple. Instead, any shred of immediate progress is cause for jubilation.

Hayne hadn't played a single snap of competitive football prior to Week 1 of the preseason. Yet there he was, running for 63 yards on five carries, adding 33 yards on a kickoff return.

So forgive us, 49ers head coach Jim Tomsula, if we're all a little excited over where Hayne came from and where he is now.

"I'd just want to temper everything," Tomsula said during a media conference call following Hayne's preseason debut, per Matt Maiocco of CSN Bay Area. "We don't need to put undue expectations [on him]. That's unnecessary to me, to put that on his plate right now."

To truly appreciate what Hayne did in that game and what he's trying to do going forward, you have to understand a little more about his journey and the intricate adjustments needed to make the rugby-to-football leap.

Hayne had been using his blend of power and speed to excel in an environment that demanded a wide range of skills. In athletic parlance—the language fluently spoken by Hayne's speed and multidirectional movement coach, Roger Fabri—rugby is a sport that stresses generalization.

Being exceedingly good at only one aspect of the game is, well, less than ideal.

"In our program here in Australia, we train very much with generalization because the athlete here has to not only perform offense, but he also plays defense and also kicks, passes and tackles," Fabri told Bleacher Report during a phone conversation. "There are so many aspects of the game."

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Fabri has been working with Hayne for seven years. As a coach, he's mastered the science of effective body movement to maximize speed in any situation, whether it's raw straight-line speed or the act of cutting abruptly in the open field.

Those movements were important for Hayne as a rugby player. But now performing them with ease and comfort is the foundation of his very existence as a running back and kick returner.

Hayne's always had a passion for the NFL, and that's been clear to Fabri. Beyond NRL training with the Parramatta Eels, Fabri also had Hayne work through football-specific drills.

Hayne's football-oriented training helped his rugby game, making it easier for him create space with small, quick cuts without losing much speed.

"We were always working on small movement patterns and executing plays and executing speed routes or speed transition movement," Fabri said.

In October 2014, Hayne announced he was leaving the NRL to pursue his American football dreams. That's when the focus of his work with Fabri shifted.

They met three times each week while Hayne was preparing for a personal showcase, his first chance to show NFL scouts he belonged. A couple of months after declaring his intentions, he held a pro day in December.

During a workout in San Diego, Hayne went through the standard underwear Olympics testing that's an annual staple of the NFL combine. Representatives from 16 teams were present, according to NFL.com's Mike Huguenin.

What video? The one in which he looks very much like an NFL player, albeit one competing against only air.

NFL player evaluation is a process of deciphering both the numbers that fill every boilerplate scouting report and reviewing game film. Often it happens in that order, because if a player's 40-yard-dash time is too slow for his position, the film might not even receive a passing glance.

Hayne recorded a time of 4.53 seconds, according to the National Football Post. He was surely pleased, and then his smile stretched just a little further by the time the NFL Scouting Combine was over.

Suddenly, Hayne was among the six fastest running backs in the 2015 class. Fabri said the 40 time was the result of improvement in a specific area of Hayne's football-focused training.

"He was always very quick and has worked on trying to improve his max velocity," Fabri said. "The area we got the most improvement from was his first-step quickness."

They worked on fine-tuning small movements for both straight-line speed and lateral agility. The emphasis was on the mechanics required to fluidly execute sudden bursts and capitalize on an emerging running lane or force a missed tackle.

There were numerous subtle yet significant nuances in movement that had to become habit.

"It is an intricate process, and I think that's overlooked, especially when you're coming from a game where it doesn't dictate that type of intensity," Fabri said when asked about the training transition. "There's so much general athleticism in the National Rugby League that's going to hold you in high esteem. You don't have the luxury of having specific movement coaches because there are so many attributes each athlete needs for success.

"You have to spend time on learning how to wrestle, how to pass, how to tackle and how to kick. There are so many components."

So far, Hayne has smoothly channeled his talents, moving away from being an athlete whose skills were applied broadly.

But there were still concerns about the Sydney native's top-end speed after his pro-day workout. One AFC executive was blunt in his assessment when speaking to Dave Birkett of the Detroit Free Press:

If Hayne's various NRL moments of glory in the open field—when he left so many sprawled bodies staring at his feet—aren't enough to silence concerns about his breakaway speed, then Fabri kindly asks for a bit of patience and perspective.

"We used to do the 40-yard dash during the Rugby League season without even the thought he may end up one day in the NFL," he said. "And he was always a consistent 4.58 to 4.64 runner. So to come down to 4.53 in only four months to prepare from the time he made his decision to when he went over is great. And with more time on more movement patterns to execute them better, I can't see why he couldn't even run under 4.40."

Yes, the man who works directly with Hayne on his quickness and ease of movement is that confident. He thinks a 226-pound bundle of muscle could eventually reach sub-4.4 speed as his NFL training progresses.

If that happens and Hayne pushes himself to a roster spot with the 49ers, the Internet should probably brace for an outage in a pretty large region of our planet.

Once you know about Hayne's story, it's hard not to join his growing crowd of cheerleaders.

The NRL offered him the richest contract in league history to remain with the Eels. Hayne told Yahoo Sports' Frank Schwab he would have been paid about $4.4 million.

His response to that offer?

"I think I'm done," he said while announcing his NRL exit, per Daniel Lane of the Sydney Morning Herald. "At this point in time, I'm done, and I think for myself and for the club it is appropriate that I move on and go forward on the next chapter of my life, give myself every chance and opportunity to take that."

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The next chapter meant his status went from rock star to rookie. And his bank account went from potentially having a historically lucrative cash flow to being guaranteed only a tick above $100,000, per Spotrac. His paychecks won't get much bigger even if Hayne makes the 49ers roster, which would get him a base salary of $435,000.

Hayne made a monumental financial sacrifice, left a sport in which he had been named the world's best player in 2009 and traveled across the world. When he first made that commitment to uprooting his life, Hayne didn't even have an NFL tryout.

He's committed to the daunting challenge and chasing his new goal in a land where, until recently, he was anonymous.

"In Australia, there is one Jarryd Hayne," Fabri said. "He went from being a superstar here to being a rookie and hardly anyone paying attention or even knowing who he is."

America knows who Jarryd Hayne is now. His name will grow exponentially on this continent if he makes it from training-camp flier to rostered player to contributor. And so will his talent as he continues to learn his new sport.