His journey to Knoxville has been a dizzying one. He was scouted during a basketball training camp in Lagos, then given a chance to impress in an NFL Africa camp in Ghana before being fast-tracked to the NFL's Academy in rural Leicestershire.

"It's happened so fast," Okoye told BBC East Midlands Today.

"I've just had to take it in. I can't take it as so much of a surprise, because I might be knocked down."

Two-time Super Bowl champion Osi Umenyiora, who made the move from Nigeria to the United States at the age of 14 himself, has played an instrumental role in Okoye's stunning rise from obscurity.

'He has a completely different level'

Umenyiora first saw social media highlights of the teenager, who stands at 196cm (6ft 4in) tall, weighs in at 104kg (16st 5lb) and has a wingspan of 7ft (2.13m) and invited the explosive youngster to the inaugural Uprise American Football talent identification camp he was overseeing in the Nigerian capital of Abuja.

Okoye has been impressing ever since, getting game time as a defensive end and on special teams.

At the NFL Academy Combine - a testing ground for potential stars of the future - he produced record-breaking results to emphasise just what he is capable of.

His 45.5in (116cm) vertical jump and 11ft 3ins (3.43m) broad jump - a leap forward from a squatting position - would both be NFL Combine

records for a player in his position and are two big reasons that Umenyiora sees a frighteningly big future for the teenager.

"I think he's probably more athletic than most people I've seen even in the NFL and they are some crazy athletes," said Umenyiora, who played as a defensive end for the New York Giants and the Atlanta Falcons.

"He has a completely different level that he has been able to get to and his numbers indicate that.

"The abilities he has are second to none and once he starts to train properly and eat properly he is just going to go to a completely different level.

"I'm actually afraid for people."

It took just three games for the Loughborough University-based NFL Academy to transform the novice into a much sought after prospect, with the University of South Carolina, Texas Tech and Vanderbilt University among the Division 1 colleges to make offers before Okoye committed to Tennessee.

"There are a lot of talented athletes, but I've got to be honest and say there are not a lot of talented athletes like him," Umenyiora said.

"Even though he doesn't really know what he is doing yet, you see flashes of what is going to separate him from everybody else."

Okoye smiles when he hears Umenyiora's high praise, but he remains focused on making this incredible one-year rise into a life-changing and career-building opportunity.

"I know he has so much confidence in me," Okoye said of Umenyiora.

"The Academy is a great place, a great programme to give you the foundations and fundamentals you need to move on to the next level.

"I just need to keep going now."