Joel James caught his first pass as a freshman at North Carolina, turned and pump-faked his defender.

Rasheed Wallace, one of the many UNC basketball alumni who return to Chapel Hill each summer to train, lost it.

“You’re bigger and heavier than all these guys by 20 pounds!” shouted Wallace, a 15-year NBA veteran now with the Knicks. “Put it in the basket!”

Welcome to the big leagues, kid. James, a 6-foot-10 Dwyer grad who plays better than 11 minutes a game for UNC, began the college-learning process after that experience. Only in his fourth year of competitive basketball, he’s part of the Tar Heels’ 10-man rotation, and his North Carolina team faces a critical test Saturday at eighth-ranked Miami.

With UNC carrying a 16-6 record and a middling NCAA Tournament résumé, the Miami game gives the Tar Heels a shot at a much-needed marquee win. The game is so important to UNC’s March hopes, James barely acknowledges the return to South Florida.

“It’s all business,” said James, who will have some 30 friends and family members in the crowd.

Basketball became the family business for the Jameses around 2009. Joel joined Dwyer’s team only after a persuasive conversation with longtime coach Fred Ross. James sheepishly asked Ross if he, 6-6 at the time, could start on junior varsity.

That year, his sister Kai, a freshman, started playing competitive basketball. She signed with Florida State this winter, just before her senior season at Dwyer. She’ll be at Saturday’s game.

“He adjusts and adapts to things really fast,” she said of her older brother. “He learned a lot in a short period of time.”

Ross and his coaching staff slimmed James from 300 to about 260 pounds over three years. At UNC, James runs the floor well and plays with more maturity than what fans saw at Dwyer.

The word “transformation” gets thrown around when discussing basketball players moving from high school to college. This time it applies.

During Dwyer’s state-title run two years ago, James often arrived late to ball-handlers and frequently fouled out. He was slow.

Now James plays more to his size while still easily running the floor as the quick-moving post man in North Carolina’s frenetic-paced style.

“I don’t know about that,” Ross said, laughing, when credited with whipping James into North Carolina form. “When he went up there this summer they got his butt in shape.”

The 6-foot-10 kid who could be found strolling through the Palm Beach Gardens GreenMarket on Sundays last winter has taken complete ownership of his freshman year at UNC.

James helped himself by staying in Chapel Hill when his teammates left for summer break. He kept playing against NBA talent and continued regular contact with Wallace and Ross.

He says he loves everything about college, including classes. Above all, James loves the learning environment created by Roy Williams and the program.

He’s rapidly growing as a player, catching up to his wise-beyond-his-years disposition. He speaks the company line now.

When he shows up in Coral Gables, hometown distractions won’t interfere with his top goal.

“It’s another game,” James said. “I just want to play my best basketball and help our team win.”