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BOSTON — Sitting in a Ritz Carlton hotel room high above downtown Cleveland just hours before his NBA debut, Jayson Tatum considers the moment. “Can you believe I’m going to be guarding the best player in the world tonight?” he asks his father Justin.

Jayson has met once before, 11 years earlier. His godfather, former high school teammate's son; he figured his godson could benefit from being exposed to basketball royalty. A giddy Jayson, wearing a red youth league jersey, even took home a picture to preserve the moment. The photo wound up in LeBron’s Twitter mentions six years later, along with a message from Jayson and a request for a follow.

Now Tatum is 19, no longer a child but also no yet yet a full-grown adult. of this summer’s NBA Draft, Tatum's future prospects, his potential, are what intrigue Celtics executives.

Tonight, Tatum is doing all he can to contain his nerves. He takes out his phone and flips through social media. He turns on ESPN and talks hoops with Justin; Justin notices that Jayson, normally reserved, is speaking more than usual. Hughes speculates about the arena's atmosphere.

Later that evening, as Jayson loosens up on the wood court of Quicken Loans Arena, he seeks out a face among the sea of 20,562 screaming observes.

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He searches for the eyes of Brandy Cole, but can't find her amongst a sea of maroon and gold. Cole was just 19 years old when she gave birth to Jayson, about nine months removed from her high school graduation. She raised him as a single mom, passing up a volleyball scholarship to the University of Tennessee. She sometimes worked two jobs at once and often tugged Jayson along to classes at St. Louis University, handing him a Gameboy and seating him in the back.

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Finding Cole during pregame warmups has been a ritual for Tatum since his days at Chaminade High School. But to Cole something feels different. Maybe it was the look in his eyes, or perhaps it was just a mother’s intuition. Here, even from her seat far away, she senses the rising tension in her son.

Two minutes into his first game, Tatum's first shot is swatted by LeBron out of bounds. LeBron is bigger and stronger then Tatum imagined. This is real.



Then in an instant, everything changes. Six minutes into the opening game of the season, Tatum stands a few yards away from ’s shattered leg.

At halftime, with the horrific reality of Hayward's injury sinking in, Tatum and his teammates reset. Tatum connects on five of his seven second-half looks and finishes the game, a close loss, with 14 points and 10 rebounds. He becomes the first rookie to record a double-double since .

Afterwards, he meets Justin outside the locker room.

“How do you feel?” Justin asks.

Jayson admits that he was initially nervous, more than he thought he'd be.

"But in the second half I felt more normal," he says. "I felt like I was ready to play."

Over the offseason general manager sacrificed depth in order to sign Hayward, and even more depth to then trade for . The bet he made was simple: quality in the NBA beats quantity. But Ainge believed that the team’s most promising young prospects could step in and fill some of those voids as the season inched along.

Hayward's injury killed that plan. In seconds, Tatum morphed from sub into one of the Celtic’s most skilled and important players.

Most lottery picks develop on younger teams where miscues are permitted and the stakes are low. But Tatum is now an integral part of a team with championship aspirations. He's one of only three players (alongside Irving and ) who could be relied upon to create a shot.

“We’re in a situation right now where we’re going to expect a lot out of those guys and we need them to be great,” head coach Brad Stevens said a week later, also referring to last year’s No. 3 pick Jaylen Brown.

The night following his debut, Tatum and the return home to Boston and welcome the Milwaukee to T.D. Garden. College and the NBA are different in so many ways, but chief among them might be the frequency of games. This will be Tatum's first ever back-to-back, and for the second consecutive night he plays 37 minutes. His legs seem to betray him: he takes just seven shots and scores just eight points. Watching every minute, Justin wonders what happened to the player he helped construct.

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Justin became a fixture in Jayson’s life following his own oversees basketball career, returning to St. Louis and becoming a high school coach. When Jayson was a fifth grader, Justin started bringing him to his varsity practices. He’d have Jayson scrimmage with his team and take part in charge drills. Jayson was never the most athletic kid, but he was smooth, strong and skilled. As he grew, eventually soaring up to 6'8", Justin escalated Jayson's training, spending hours and days with him in local gyms.

Justin knows what kind of player his son is. Jayson just needs some time—a day, a week, a month—to adapt to the NBA game. But with Hayward now out indefinitely, there's little room for growing pains.

“I’ve got to learn on the fly,” Tatum told reporters recently. “But that’s how to learn, by being out there on the floor.”

The hold on for a victory over the . That night, Tatum returns to his apartment, but not before stopping by Cole’s home, two floors above. She cooks him tacos. Normally he hates mixing different foods—if there’s a plate of chicken and rice, Tatum will eat all the chicken first before taking a bit of rice—but anything in the sandwich family gets an exception.

They sit there in the kitchen with their two Boxer dogs, the eight-and-a-half year old Lenox, and the 15-week old Creed, and look back on the whirlwind 48-hours Jayson had just endured.

“They need you,” Cole tells her son. “Make the right basketball play, but trust the instincts that got you here.”

One minute and 10 seconds into the fourth game of his career, Tatum soars through the air and with his right hand viciously slams a missed jumper down over the head of New York guard Jr. The Boston crowd erupts.

Before the game he stood in the locker room and fielded questions from a pack of reporters about his first week in the NBA. How was he processing the experience? Was he enjoying it? Overwhelmed? Where did he feel he was struggling?

“Sometimes I just think I play too fast and think about the plays and swinging it,” he said. “Sometimes when I’m open, I don’t take shots. But the guys out there, they put confidence in me to tell me when I’m open, to shoot.”

There are times, he added, when he’s on the floor and sees All Stars like Irving and Horford running alongside him, players he grew up watching. He can’t help himself from thinking his job is to just get the ball into their hands.

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But on this night something changes. Maybe it’s the dunk, maybe it’s just a natural growth, maybe it’s a mix of both, but he torches the , unleashing an arsenal of offensive weapons. There are Kobe-like pivots and Wade-esque blocks, fast break dunks and feathery jump shots. Tatum finishes the game, a blowout win, with 22 points, four steals and two blocks. He buries four of his six three-point attempts. He carries the offense for stretches of time.

He's shooting when he's open and looking to score even when he's not. His slithery game reminds of great , who Justin had Jayson study as a kid. Tatum has defenders reaching and lunging; he's already drawing shooting fouls more frequently than 90 percent of the league, according to Cleaning the Glass. He's too big for small wings and too smooth for large ones.

“He’s the typical guy that I think teams in the league are looking for,” head coach told reporters the morning of his matchup against Tatum. “An athletic guy who has length, can drive the ball to the basket, can shoot the ball and can make plays, can switch on different guys, so he’s a great player, that’s why he was a high pick.”

After the win over the , Tatum tells Cole not to wait up. There are no postgame meal requests. It’s Brown’s 21st birthday, and the team is celebrating.

Cole begins making her way out of the arena, before receiving another text. It's from Tatum. “Are you gone?” it reads. Tatum showers, speaks to the media and walks down the hall to a family lounge.

Cole gets on Jayson about his poor rebounding; after pulling down 27 in his first three games he reeled in just four tonight.

Jayson's lips curl into a smile.

“I was hooping, huh,” he says.

Yaron Weitzman covers the and NBA for Bleacher Report. Follow Yaron on Twitter, @YaronWeitzman, and listen to his -themed podcast here.