The calls started coming in over the past two springs as Giannis Antetokounmpo's talent began to come into focus. Trainers to some of the NBA's top-level superstars wanted Antetokounmpo to work out with their clients during the offseason. Among the suitors was LeBron James' camp -- the NBA's equivalent of being tapped for Skull and Bones, the society of the young NBA elite.

Members of the Milwaukee Bucks' front office and coaching staff encouraged Antetokounmpo to take LeBron up on the invitation. What better way to hone one's game than training with the best player in the world? But Antetokounmpo would have none of it. Though he has a baller's appreciation of James and his place in the game, the Bucks' franchise player has no interest in following LeBron around like a puppy. Besides, why would he want to give his fiercest Eastern Conference rival a free look at his tendencies, vulnerabilities and anything he might be working on for the upcoming season?

Summer was for the Greek national team, for family and for grinding at the Bucks' training facility or wherever business took him. For Antetokounmpo, Bucks assistant Sean Sweeney -- and not LeBron or Kevin Durant or anyone else -- would be his preferred workout partner.

Antetokounmpo's thanks-but-no-thanks provides a small window into what kind of superstar he might be as he takes up residency in the NBA's pantheon. His response wasn't so much a tacit rejection of the NBA brotherhood, as James likes to call it, as it was a strong signal from Antetokounmpo that he plans to craft a superstar persona that's decidedly less social, less entrepreneurial and more introverted than the prevailing trends of the LeBron era.

Antetokounmpo recently read "More Than A Hero: Muhammad Ali's Life Lessons Presented Through His Daughter's Eyes" by Hana Ali. The book was part of an exchange with Antetokounmpo's girlfriend, whom he gifted "Me Before You," a love story by British novelist Jojo Moyes. ("So far it's working," Antetokounmpo says of the transaction.) What struck Antetokounmpo most profoundly was Ali's admission that his mental and spiritual lives weren't truly fulfilled until his retirement.

Giannis Antetokounmpo has been drawing comparisons to LeBron on the court. AP Photo/Aaron Gash

This detail inspired Antetokounmpo to take inventory of his own life, as he entered his fifth season in the league. When he gets out of bed in the morning, he said, the focus is entirely on basketball, on getting his joints loose, on drawing up a to-do list in his head for what's in store when he gets to the Bucks' gleaming new facility in downtown Milwaukee. Whatever is left over goes to his family.

"What Ali said is true," Antetokounmpo said.

Does it make him sad to believe that being his best basketball self and being his best spiritual self are incompatible?

"No, that's just the way it is," he said. "Now I have something to look forward to in 20 years."

Antetokounmpo's diagnosis of an NBA career as an all-encompassing one speaks to his outlook on stardom. Still only 22 years old, Antetokounmpo has revealed to the Bucks, the media, sponsors and the NBA fraternity a short priority list composed of basketball and family as interchangeable Nos. 1 and 2.

He has been the family's breadwinner and primary decision-maker for the past several years. Though that's not an atypical reality for an NBA player, few pro athletes maintain the kind of physical proximity Antetokounmpo has. Since arriving from Greece, Giannis' parents (his father, Charles, passed away just prior to the season) and his two younger brothers have lived in the same home, complex or apartment building. After games, Antetokounmpo doesn't frequent Milwaukee's growing collection of top-notch eateries, opting for a family dinner at either his or his mother's apartment.

"Living at the facility" is a popular label ascribed to NBA workaholics ("gym rat" is passé), but in the case of Antetokounmpo, it's barely an exaggeration. Weeks before the official start of training camp, Antetokounmpo can spend more than 10 hours at the Bucks' training center -- practice and drills in the morning, film and individual work at "night school" in the evening. This is where Antetokounmpo refines the qualities he wants to define his stardom -- meticulous preparation, killer mentality, the kind of intensity that strikes a visceral fear in the heart of his opponents.

This regimen, coupled with the absence of an active extracurricular life, prompts some of those close to Antetokounmpo to draw a parallel with the superstar persona crafted by Kobe Bryant. You won't find Antetokounmpo aboard a banana boat. Like Bryant, he has little interest in keeping company with fellow NBA players, though he has developed a close friendship with Thon Maker. When asked recently whether the Bucks routinely go out to dinner as a team, Antetokounmpo replied that on each occasion they had last season, they'd been blown out the next game. For Antetokounmpo, team-building occurs at the arena and at the facility, leading with his intensity and work ethic. He cited teammate Khris Middleton playing through a severe sickness in Game 6 of the Bucks' playoff series against Toronto last April as the sort of event that bonds a team far more than group dinners or goofing on the team plane.