Grant Halverson/Getty Images

When basketball minds speak of the phenom they watched playing for the U.S. national team on the shores of the Mediterranean Sea in the summer of 2015, they do so in hushed tones, their voices filled with awe.

The Harry Giles they saw on the Greek island of Crete in the 2015 FIBA Under-19 World Championship was the stuff of legend.

"The potential just looked endless," men's national team director Sean Ford remembers of the now-Duke freshman. "Casually hitting threes. Rebounding everything. Running the floor. Blocking shots. There weren't any weaknesses."

Ford claimed Giles was as good a player as had ever come through USA Basketball's system. Playing on a team that also featured now-Kansas Jayhawk (and possible 2017 No. 1 overall pick) Josh Jackson and now-Duke teammate (and certain 2017 lottery pick) Jayson Tatum, Giles was alone on another level.

"Harry to me was as impressive as Kevin Garnett as a young guy, as impressive as Chris Webber as young guy," says Archie Miller, one of the assistants on that national team and Dayton's head coach. "He had it all. I would have drafted him No. 1 immediately after that."

Playing against professionals as a 17-year-old rising high school senior—only two months after his 17th birthday, mind you—Giles dominated the competition. Scouts saw an elite rebounder. A spectacular athlete. An enviable combination of motor and touch. The perfect basketball build, so long and so powerful.

The type of player NBA teams tank their seasons for.

Video Play Button Videos you might like

"He was just a freak," said Jonathan Givony, who runs DraftExpress. "He was just a level above everyone else in his age group athletically."

Brace Hemmelgarn/Getty Images

It's difficult to reconcile that player with the one we see now, floundering around for the 18th-ranked Blue Devils.

Four months after he captured so many imaginations in Greece, Giles tore the ACL in his right knee. It was his second ACL injury in high school, as he tore the ACL, MCL and meniscus in his left knee in 2013 while playing for USA Basketball's U-16 team, per ESPN.com's Dave Telep. He rehabbed and seemed primed to star at Duke this year, but he suffered a setback shortly before the season: arthroscopic knee surgery. The singular talent who was once the hands-down No. 1 overall pick in the stacked 2017 draft has so far played exactly 149 minutes in 12 games at the college level, averaging 5.3 points and 4.6 rebounds.

His confidence seems shattered. His timing appears off. He's a step behind everyone else on the court. A guy who used to fly is now missing dunks.

He's gone from sure thing to enormous mystery.

There are many questions left to be answered between now and June 22, when NBA Commissioner Adam Silver strides to the podium, looks down at a slip of paper and says, "With the first pick in the 2017 NBA draft…"

Which point guard will go first overall, UCLA's Lonzo Ball, Washington's Markelle Fultz or North Carolina State's Dennis Smith Jr.? (Or will it be Jackson, or even Florida State forward Jonathan Isaac?) Which one-and-done players will show off crunch-time skills in the NCAA tournament? Who will impress at the scouting combine? Misinformation will intermingle with good information until, finally, the commissioner announces the picks.

But perhaps no question is more intriguing than whether Giles will be among the names Silver announces.

Should Giles opt for the 2017 draft and hope an NBA team banks on him becoming the player he used to be, despite scant evidence of that this season? Or should he return to Duke for a sophomore year where the risk—putting his body on the line without any guaranteed money—is as big as the reward of possibly becoming the top pick in 2018?

To answer these questions, I spoke with scouts, front office executives and agents about The Legend of Harry Giles—the player who captured the attention of the basketball world two years ago—and The Question of Harry Giles. Should he go, or should he stay?

The majority of basketball insiders I asked say there's a simple answer to a simple question: If you have a chance to become a millionaire, you take it.

Right?

Maybe not. Other front office executives come to the conclusion that Giles needs to return to school but hedge his bet.

There's more give and take to the situation than a simple answer provides.

One front office executive says if Giles comes out this year, a team will take a flier on him somewhere between the 11th and 18th picks, even with the health risk. That's how great his potential is.

On the other hand, he can take a risk on staying healthy during a second year in college—and the reward could be far more money.

Let's say Giles decides to go to the NBA after this one injury-hampered season at Duke. If he is picked 17th this June, which is where DraftExpress projects, Giles' rookie contract would be worth an estimated $10.1 million over four years, per RealGM. If he comes back for his sophomore year and tears up college basketball like he tore up the FIBA U19 World Championship, he could go No. 1 overall in 2018. That contract would be worth an estimated $31.1 million—$21 million more than if he's picked 17th in 2017.

What happens if he stays and has a similarly disappointing sophomore season? For the sake of argument, let's assume a team will still take a late-first-round flier on him based purely on upside. If Giles is the No. 30 selection in 2018, he'd still net an estimated $7.4 million over four years—only $2.7 million less than if he were to go 17th overall in 2017.

Lance King/Getty Images

Of course, the big risk is this: What happens if he suffers a third ACL tear or a similarly devastating knee injury that strikes fear into NBA teams?

He may never see a dollar.

"[Returning for a sophomore year] sounds really smart until he comes back and tears his ACL again—and then his career is over," Givony says. "Maybe getting a guaranteed NBA contract is not the worst thing in the world when you've had this history with knee injuries."

That line of thinking goes like this: In the NBA, big money comes with the second deal, not the first. If you're going to put your fragile body on the line, don't do it when you're playing for free in college. Do it when you already have money in your pocket—when you can play without abandon, knowing that if you get hurt again, you won't suddenly go broke.

It's like you've made it through the first 13 questions on Who Wants to Be a Millionaire. You're already sitting on $500,000. You aren't 100 percent sure you know the answer to the 14th question, but you think you do. Do you go for it, trying for $1 million with the risk of leaving with nothing? Or do you walk away with the money already safely in your pocket?

Underscoring the mystery that Giles represents: There were at least two scouts from every NBA team at Duke's 84-74 road win over Notre Dame on Jan. 30, according to one scout who was in attendance. They came largely to see Giles. He got in early foul trouble and ended up playing nine minutes, finishing with four points and five rebounds. That's not exactly the stat line of a high lottery pick.

Yet even in that disappointing taste of his NBA potential, Giles still gave scouts some catnip. Duke was up six with less than three minutes left when guard Grayson Allen missed a jumper. The ball popped straight up off the rim.

"And Giles grabbed that ball in a place in the air where no one else in the building could even think about going," the scout says. "And I said, 'Wow. Wow.'"

Lance King/Getty Images

"He'll be taken in the first round this year," another scout says. "If he comes back healthy next year and plays, he's a top-five pick easily. But no one has a crystal ball. What happens if he goes down?"

As ESPN's Jay Bilas told Bleacher Report, this is a decision filled with nuance and mystery. For every point, there's a counterpoint that's easy to argue.

"He should do what he feels is in his best interest for the long term," Bilas says. "Who cares where you're drafted? They're giving money away up there. The issue is for him to have the longest and most productive career and the longest and most productive life.

"I tend to think the players who've stayed in college a little bit longer feel better about it. But that's not true in every case," Bilas continued. "I happen to think Harry Giles is the real thing. His physical health is the wild card. And I don't know how to process that. Do you say, 'I don't want to take a chance something's going to happen. I don't want any risk taken as a forced amateur anymore?'"

Another factor is that Duke may not be the best place to develop his game right now. The Blue Devils are playing this season without a true point guard. Because of that, their offense hasn't been particularly smooth. It's been tough to run plays for Giles. So he's found himself in limbo: He missed all of the preseason practices as well as his team's first 11 games. He's not incorporated into the offense. And on defense, he's been a huge liability in defending pick-and-rolls—something he would have learned had he been able to practice in the preseason.

One person who knows a lot about the fragility of basketball health is fellow Dukie Jay Williams. The Chicago Bulls picked him second overall in 2002, but after his rookie year, he was in a serious motorcycle accident that ended his basketball career. At the beginning of this season, Williams, now an ESPN college basketball analyst, said he didn't believe it was in Giles' best interest to play for Duke at all.

"He was top-five pick, and his stock didn't have anywhere else to go but down," Williams said. "Now he's faced with a difficult decision. And don't think for one second Harry Giles isn't checking draft boards. He is. He came to college with the intention of being a one-and-done player. Sometimes when you have pressure on your shoulders like that, it gives you a tendency to be more tight, especially when you're battling injury."

After surveying college and NBA sources, I came up with no consensus. But I did come up with my own nuanced advice for Giles, advice that one Eastern Conference executive vehemently agreed with.

Before I give that advice, a disclaimer: There is a certain amount of sleaze in publicly debating the pressure-packed decisions of an enormously talented 18-year-old basketball player. Giles has dealt with higher basketball highs and lower basketball lows than any elite NBA prospect in recent memory. Whichever decision he makes will be doubted and second-guessed. But he is, after all, a human being, and there are real concerns other than just dollars and cents. Does he like Duke? Does the basketball system there play to his strengths? Does he like being a college student? Is the academic part of being a student-athlete an annoyance or a joy? Does his family need the money?

And perhaps most of all: Can a guy who expected to have the option to become a one-and-done high lottery pick wrap his mind around returning to college for his sophomore year?

Grant Halverson/Getty Images

But as the mobster Hyman Roth declared in The Godfather: Part II, "This is the business we've chosen." Part of the process of becoming a professional athlete is becoming a commodity—a piece of meat that's poked and prodded, someone whose private decisions are publicly questioned.

My advice: Giles should return for his sophomore year. He should bet on himself. And he should hedge his bet—not by playing with fear but by taking out a massive insurance policy. Elite college athletes take out insurance policies all the time. Clemson's Deshaun Watson had a $10 million policy; so did Jameis Winston and Teddy Bridgewater.

Giles is the only one who knows his own body. And if he feels he can regain what he once was, he should make that bet.

One Eastern Conference executive explains it like this: Since Giles did play this season, he should come back for another season. One justification for leaving school is that an NBA team is a better place for injury rehabilitation, but the executive brushed that off: "He's at one of the only programs in the country he should stay at," he says.

"It would be to his advantage if he comes back and plays without abandon," he adds. "What I see now is him playing with the fear of getting hurt again. You can't play that way. He needs to play—to really play. And he can be capable of being special good if he gets right."

But there's that nagging word that lingers over Giles' life: If. If he gets drafted in the lottery this year. If he passes medicals. If he can survive a whole college season without another major injury. If a team will take a flier on such a risky commodity. If, if, if.

There's no certainty in the case of Harry Giles, despite the fact that less than two years ago, he seemed as sure of a thing as you can get. There's no easy answer.