Leki Fotu's high school rugby highlights are making the rounds on social media, and they are unfair.

The Cardinals' fourth-round pick was not only way bigger than anyone else on the pitch, but somehow faster than most, too.

Fotu's rugby ability was so promising that he played for the USA Rugby Boys High School All-American team, and even trained in England with the London Wasps in 2013.

Fotu, who is of Tongan descent, sat out football his junior year of high school, and upon transferring to Herriman High in Riverton, Utah, had a critical decision to make for his future: rugby or football?

"I had a talk with my mom, and the best interest was to finish my education and to see where football would take me," Fotu said. "It was just a better option for me to pursue this."

The beneficiary of the decision was Herriman coach Dustin Pearce, who quickly realized an athletic specimen had dropped into his lap.

"Our first day at our team camp in Southern Utah, we put him in at tight end," Pearce said. "We call the outside shade of a tight end the 9-technique, and the dude was set up at like a 15, and Leki took two steps and was so explosive off the ball that he reached the kid. I was like, 'Whoa, we've got something serious on our hands.'

"And then, on the next series, we were on defense and it wasn't even funny. The way that he ran, and his effort, and his physicality, it was over the top."

Fotu's natural ability shined on the gridiron, and several colleges quickly pursued him. Utah won out, but the lack of specialization kept him behind the 8-ball on technique, so the transition took time.

Fotu only amassed 23 tackles and didn't have a sack as a defensive linemen in his first two years of college.

"There was a learning curve for him," Pearce said. "When we had him, we only had him for one fall, and he was raw. He hadn't been taught technique. He hadn't been taught scheme. He just survived on pure athleticism and his size. It took him some time to develop.

"I think he was just frustrated, because you go from being the most elite high school player in the state of Utah to going over there and being humbled pretty quick. They're men, especially the defensive line at Utah."

Despite the slow start, Fotu said there was never any second-guessing about his decision to choose football over rugby.

"Once I made my transition back to football, there wasn't really any regret," Fotu said.

The breakout came as a junior, as Fotu had 34 tackles, 3½ sacks and six tackles for loss in 10 games. His numbers dipped as a senior, but Fotu was again a steady anchor on the defensive line, making life tough on ballcarriers attempting to run up the middle.

While he no longer played rugby, Fotu believes some of the lessons he learned on the pitch were beneficial.

"In rugby there's no pads or anything involved, so when you come back to football wearing pads, you have the courage to do anything," Fotu said. "Everything that I did with that sport definitely helped me out with my athleticism and the way that I move inside for the position I play."

Fotu's lack of early specialization may be a blessing. He has only focused on football full-time for four years, and thus, his ceiling may be higher than others who are more polished.

"I haven't really unlocked everything yet," Fotu said.

Many believe he will be a run-stuffer in the NFL whose value will come primarily on early downs. Cardinals defensive coordinator Vance Joseph believes there is more lurking.

"When you look at Leki's size, everyone assumes he's a run-stopper," Joseph said. "The scheme they played at Utah, he was coached to keep the linebackers clean. He's more in a square stance, catching gaps, eating blocks. But when you watch this guy move and run, once you put him into an attack stance and allow him to go vertical and be disruptive, he's going to be also a pretty good pass-rusher, as far as pushing the pocket."

Fotu chose football over rugby in part because it was the easier way to secure a college scholarship, which kept his mom from having to pay tuition. On the field, Fotu is similarly unselfish, often taking on blocks for others to get the glory.

While Fotu doesn't crave credit, Pearce beams with pride seeing the gentle giant he encountered as a teenager make it to the NFL.

"Leki deserves everything he's getting right now," Pearce said. "He's a very selfless person, a very hard-working kid who cares about others more than he cares about himself. This is Leki getting his payback for everything he sacrificed."