Devin Booker found a surprise in the Spurs visitors’ locker room on Nov. 23. It wasn’t quite the live rattlesnake Thomas Robinson and the Trail Blazers encountered in the San Antonio AT&T Center in May of 2014, but the Suns rookie did learn of a monumental career milestone.

Booker, a key spark plug off John Calipari’s bench at Kentucky last year, never started a game during the Wildcats’ flirtation with an undefeated season. Just 14 games into his professional career, Booker discovered his name scribbled in the starting lineup on the room's large whiteboard, in place of the injured Eric Bledsoe.

“I was nervous,” Booker tells SI.com. “I was just like, ‘wow, I guess it’s go time.’” At 19, Booker became the second-youngest player to start an NBA game since the 2005 draft class—the final group to include high schoolers—and the youngest starter in Suns history. “I’m out there with Tim Duncan, Tony Parker, Manu Ginobili, people that have been in the league since I was two years old,” he continued. “It was surreal, just being out there with legends.”

Suns rookie Devin Booker's shooting stroke tailor-made for today's NBA

Booker became one of Phoenix’s regular starters after Bledsoe suffered a torn meniscus in a Dec. 25 loss to the 76ers and was lost for the season. Bledsoe’s injury punctuated a dismal start to the Suns’ season that was followed by public questions about head coach Jeff Hornacek’s job security.

The Phoenix rookie has been a rare silver lining to emerge from those ashes. He has scored 15.4 points, corralled 3.2 rebounds, and created 1.7 assists in 30.4 minutes per contest in 11 games as a starter—numbers fittingly similar to the rookie season for Klay Thompson, a common comparison for Booker. On the season, Booker is shooting 44.6% from three-point land, which would rank sixth in the league if he had enough attempts to qualify.

“He’s a smart player. He knows how to play the game,” says Hornacek. “A lot of guys that get into this league with only one year of college, they don’t really know how to play the game. They’re talented, they can do things individually, but the whole team defensive concept, when to make the right pass with the quickness of the NBA, he has that.”

Booker’s exposure to professional basketball started before the typical rookie. His father, Melvin, played a handful of years in the NBA for the Rockets, Nuggets, and Warriors in the mid-1990s and played over a decade in the CBA and overseas.

A 12-year-old Booker visited Melvin during one of his several seasons in Italy. Booker attended all of his father’s practices, gluing his eyes to Melvin’s teammate and then 18-year-old, elite NBA prospect Danilo Gallinari. “I was starstruck,” Booker says. “NBA scouts were coming to see him. I remember after practice him signing his shoes for me and just messing around and playing one-on-one.”

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Booker’s Suns are 2–1 against Gallinari’s Nuggets so far this season. “It’s just crazy, five, six years, just everything that could happen,” Booker says. “He’s like a big brother to me. He always goes like this,” Booker pauses to raise his right hand parallel to the floor, even with his chest, “‘I remember when you were this big.’”

Booker visited Melvin’s Mississippi home during the summers prior to permanently migrating south from Michigan for his high school years. From there, father and son did extra drill work before and after practices at Moss Point High School. In the summers and on weekends, they endured rigorous beach workouts. Melvin would first demonstrate ladder drills and other exercises focused on improving explosiveness. Booker would wear a weight vest on his upper body, strap leg weights to his ankles, and play copycat as he trudged through the sand.

Just a year ago, Booker didn’t expect to be in this position. Recruited to Kentucky as a secondary cast member on Calipari's loaded squad last winter, he arrived in Lexington expecting to play at least two seasons. “Me and Tyler [Ulis], at first we had to see if we were even going to play or not,” Booker says. He quickly earned a reputation as the premier shooter in last June’s draft, fast-forwarding his career trajectory.

Booker believed the Hornets—ranked dead last in the NBA in three-point shooting last season—had him slotted at No. 9. The Heat also expressed serious interest at No. 10, but were lured by the raw athleticism of Justise Winslow. As he slid to No. 13, the Suns offices in Talking Stick Resort Arena celebrated. “As it kind of got closer to us, we got more confident,” says Suns assistant GM Pat Connelly. “You just sit there and hope that he was gonna be the guy that would be available for us at 13.”

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. “Obviously, his shooting was his main piece, but the rest of his package was also really appealing,” Connelly says. Phoenix is more than pleased with how Booker’s body has developed in only half a season with Suns strength coach Mike Elliot. And Booker isn’t solely focused on jump shots. Instead, he’s frequently attacked closeouts with an array of strong drives to the rim.

Booker is an above 40% shooter as a pick-and-roll ballhandler, per Synergy Sports. He’s been an absolute terror in transition as well, blurring past defenders lethargically retreating from one end of the floor to another. “It’s a combination of strength and feel that he’s been better at doing this year,” Connelly says. “It’s been a nice development. In time we thought it would come.”

His quick start has turned heads across the league. “Klay said, ‘Man, it feels like I’m looking in a mirror,’” Booker says. This summer, he bumped into Rip Hamilton, a childhood paragon for moving off the ball. “Rip was like, ‘I like your game,’” Booker says. “You expect them to watch basketball but not to watch you and actually like your game when you’ve been watching them your whole life. KD said [during a game], ‘What’s up, Book?’ I don’t know how he knew everybody calls me Book.”

At the conclusion of his twitter bio, Booker has written #StillChasin’, a motto many suspected was in relation to Kentucky’s quest for an undefeated season. He’s still hungry after reaching the Final Four and emerging as a legitimate NBA starter. “No, I’m still chasing my dreams,” Booker says. “I want to be like Tyson [Chandler] in the league, 15 years in, be a legit vet. That’s when I’ll say I’m done chasing.”