Even if you can process a playbook, two-time Super Bowl winner Umenyiora points to something called the ‘planet theory’, external as a major obstacle for NFL hopefuls like Rees-Zammit.

Espoused by late New York Giants general manager George Young and their legendary head coach Bill Parcells, the theory states there are only a few humans on the planet who have the ideal size and athleticism to succeed as offensive and defensive linemen, thereby making them more valuable.

The opposite is true at running back and wide receiver, which along with quarterback and tight end are considered American football’s ‘skill positions’.

They are the positions Rees-Zammit tried his hand at and, after last week’s decision, he mentioned how so many similar players were competing for a spot on the active roster.

“I think Rees-Zammit is a fantastic athlete, but in terms of pace and athleticism, there’s maybe 500 of those guys in Florida alone, so it’s usually a lot more difficult for players like that,” said Umenyiora.

“You have to be unparalleled. You have to be superior athletically to be able to learn the game and then break through.”

Rees-Zammit is one of the fastest players in world rugby, he registered 4.43 seconds for the 40-yard dash, external but that put him just joint-27th among the players eligible for last year’s NFL Draft.

But even if he was the quickest, players new to the NFL need time to catch up on the “football IQ” their rivals have already developed, says pundit Phoebe Schecter.

“The key factor is the ability to take what’s learned in the classroom and apply it at elite speed on the field because players can overthink it, there can be paralysis by analysis,” she added.

“And from a rugby perspective, your instinct is to find space, but in American football you shouldn’t necessarily do that, you should follow your blocker.”