If Jack Sock is to realize his vast potential, the time for him to start doing so is at the U.S. Open

Memorial Stadium in Lincoln, Neb., where the state’s beloved Cornhuskers play college football, can hold 87,000 red, white and maize-clad crazies. The fan-to-athlete ratio is about 725 to 1—a sizable gulf, but not nearly as staggering as one that two Nebraska natives experienced five years ago, on a tennis court some 1,300 miles to the east.

“That Friday night, when I was playing in Arthur Ashe Stadium against Andy Roddick, a guy I grew up watching, in one of his last U.S. Opens,” Jack Sock pinpoints as the moment he entered a different phase of his life. A few months earlier, the 18-year-old had completed an 80–0 high-school singles career. Two days earlier, he had recorded his first ATP win with a punishing and relentless style of play which seemed an ode to Roddick, his opponent in an all-American match made for the 23,000-seat arena.

Sock acquitted himself commendably in the prime-time contest, losing 6–3, 6–3, 6–4. When it was over, Roddick shook Sock’s hand at net and told him, “you’ll be out on that court many more times.”

Five years later, much has changed in sports. But for the fast-swinging Sock, change has come slowly. His pristine high-school record follows him, for better or worse. He still hears and reads the groan-inducing puns of his last name. (“Got used to those,” he says.) He’s probably asked more about his 2014 Wimbledon doubles title than anything he’s achieved in singles, though that might change after winning mixed-doubles gold in Rio de Janeiro. He’s ranked inside the Top 30, but according to Sock, there’s “definitely room for me to improve.”

The question of who will be the next great American man remains at the tip of the casual fan’s tongue. Will Sock become the answer?

“Jack is progressing nicely,” says Jim Courier, the United States’ Davis Cup captain. “He has worked hard on his fitness and developed a good understanding of his weapons and how to best deploy them. The future is exciting for Jack.”

It’s a natural time to take stock of Sock because, frankly, he’s the most intriguing American prospect in years. There’s his unorthodox path to the pros. There’s his forehand, which, according to Tennis Channel, generates more RPMs of topspin than Rafael Nadal’s. And while he’s had success on grass, he prefers clay, a traditional quicksand for U.S. men.

Sock’s lone ATP title came on red clay, in Houston last season, and he proceeded to reach the fourth round at Roland Garros. This year, however, Sock fell one win short of defending each of those career-best results: He lost to Juan Monaco in the Houston final and fell in the third round on the terre battue to Albert Ramos-Vinolas.

“He should win the match he played today,” said Paul Annacone, former coach of Pete Sampras and Roger Federer, after Sock’s shortcoming in Paris. “I didn’t love some of his tactics: played too deep on return against a guy with a very average serve; got too complacent with his court position at times; still has to work on his shot-selection discipline in rallies.

“All of this is just part of the process.”

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The process began when, according to Babolat’s tongue-in-cheek “Jack Sock for President” ad campaign, Jack was “born in America’s bread basket, in an actual bread basket.” Sock indeed grew up in Nebraska, where he lived through the sixth grade. Part of an athletic family, Jack was exposed to golf—which his dad, Larry, plays regularly—and tennis, which his mom, Pam, played recreationally. Jack and his older brother, Eric, play both sports today, but as boys it was tennis that they pursued.

“It wasn’t pushed on me by any means, but I happened to find a tennis racquet and got into some clinics when I was younger,” Jack says. “I remember watching [Andre Agassi’s] Bollettieri instructional videos when I was a kid.”

Another tennis academy soon consumed Jack. Located about 200 miles southwest of Lincoln in Overland Park, The Mike Wolf Tennis Academy would provide Jack with the resources necessary to harness his proclivity for the sport. Week after week, Pam would drive her sons to the acclaimed tennis center. In seventh grade, Jack and his family relocated to Kansas City.

It was worth it. And though Jack didn’t realize it then, the move away from Nebraska foreshadowed his decision to eschew college and start a career in the pros.

But even as a globetrotting pro, Jack never seems to be far away from home. When he won the doubles title at Wimbledon, he brought his dad to the Champion’s Dinner. During the last two French Opens, the first thing Jack did each morning was check on the Kansas City Royals. (“It was stressful but almost less stressful because I didn’t have to sit through the game, be all nervous and anxious,” he says.) He has purchased a residence in Overland Park; in the basement is a photo mural of Jack serving, with Eric and his dad clearly visible in the stands.

Jack was home more than he would have liked in early 2015. Pelvic surgery sidelined him until March, but worse, Eric had contracted Lemierre’s syndrome, a rare bacterial disease. Bedridden in a hospital for three weeks, Eric was fighting for his life.

To everyone’s great relief, Eric recovered. This year, Jack’s visits home are once again trips he relishes. Two weeks before Wimbledon, while many pros were in Europe hitting on grass, Jack remained in Kansas City. When the topic of baseball was broached, Jack interjected: “Actually, a couple of my friends and I are headed to the Royals game right now.”

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While Sock can always come home, he has a more limited window in which to make an impact on the sport. To do so, he’s enlisted the help of coach Troy Hahn.

With an eye toward greater success in singles, the team is expected to cut back on doubles.

One thing people seem to agree on is that Sock remains a work in progress, albeit one with vast potential. Courier calls him, “one of the best athletes in the game.” Annacone cites the 23-year-old’s “very high ceiling, as his strategy, fitness and discipline all mature.” Tennis Channel commentator Leif Shiras says Sock is “one of my favorite players” to watch because of his extreme forehand grip.

“He’s making decent progress,” ESPN commentator Brad Gilbert adds. “I think he has to improve his backhand, because right now he relies on going from alley to alley and hitting forehands. I think he can improve his serve more and his fitness level. If he can improve those three areas of his game, he could make a run to the Top 10.”

Sock earned his 80th win in the pros earlier this year—tennis’ valedictorian is doing just fine in the real world. It’s the next five years that will determine whether Sock becomes the next Roddick, or just another in a long line of U.S. men who have tantalized with talent but ultimately disappointed.