Al Horford was destined for greatness. His mom knew it all along.

BOSTON – When Al Horford was seven years old, he decided he wanted to be an NBA player.

One afternoon, as they walked in downtown Santo Domingo, he turned to his mother, Arelis Reynoso, and informed her of his new aspiration.

“I remember it like yesterday,” Horford said. “We were walking on the street, and I was telling her, ‘Hey, I feel like I made a life decision. I want to play professional basketball and play in the NBA.’ And she was like, ‘Absolutely.’”

In the back of her mind, Reynoso had always wanted her son to play a different sport: baseball, which her father played in the Dominican Republic.

Her son had different goals, and as soon as she learned of them, she made the resounding decision to do everything possible to support him.

“I really believe every mother needs to understand — it’s not our dreams, it’s their dreams,” Reynoso told CelticsBlog.

It’s a conversation that Horford still remembers as integral to his journey of becoming an NBA player.

“Her saying that for me was so powerful because I felt like it came from her heart, and she believed it, and that gave me a lot of confidence,” he said. “I didn’t know how I was going to get there, but I had the dream, and that’s all it took. If her reaction had been different, I don’t know what would have happened.”

Al Horford’s leadership and basketball IQ was apparent from a young age

Teresa Duran, a women’s basketball legend in the Dominican Republic, was one of the first people to coach Horford at his first basketball camp. Right away, she was stunned at his basketball acumen, and shared with his mother that she’d simply never seen a little kid exhibit that level of court vision and IQ.

Almost immediately, Horford began acting as a coach to his teammates — writing down plays, giving advice, and explaining how to make on-court reads.

“He [would] say, ‘Come on. Let me show you. When I’m here, you need to pass the ball here, but if you see two players here, you need to do this,’” Reynoso said, reminiscing on how her son instantly took over the coach’s seat.

It was also obvious from the jump that Horford didn’t mind the physicality of the sport. In Santo Domingo, where he and his mother lived, there were no indoor basketball courts — so kids instead competed on concrete outdoor courts.

And, as he regularly got bruises and bumps from diving on the concrete, his mother reminded him that baseball could serve as a less painful alternative.

“He [would] say, ‘No, mommy. That’s okay. This doesn’t bother me,’” Reynoso recalled.

Meanwhile, off the court, Horford began to religiously study the game, seemingly treating basketball as a profession from the moment he decided he wanted it. While most kids simply wanted to play pickup in the park, 10-year-old Al buried himself in literature.

“I just found books [about] basketball, and he started reading the rules,” Reynoso said. “He starts seeing how the referees have a protocol and etiquette… he wanted to know everything. And every time he saw anybody play, he wanted to be there, watching and playing.”

Eventually, Horford needed more training than the DR could offer to continue elevating his game. So, every other summer, his mother sent him to basketball camps in Miami.

Throughout his youth, he competed in a slew of other sports — track and field, volleyball, soccer, and baseball — before moving to Michigan for high school, where his father, former professional basketball player Tito Horford, resided.

At first, Horford was overwhelmed at the perceived talent disparity between him and the other Grand Ledge High School athletes. So, he explained to his parents that he needed to spend three hours after every high school practice working on his game. His mother now lived 2,000 miles away for the first time, but he called her regularly to detail his plans.

“‘Mom, I need to be in the same level the players are in my high school team, so I need to work after every day.’” Reynoso recounted.

In a flash, he became one of the school’s most dominant players.

He made a similar leap at the beginning of college; at the University of Florida, Horford was disappointed to learn he wouldn’t be one of the team’s starting players at the beginning of his freshmen season.

When he called his mom to let her know, she told him she had no doubt he’d soon be inserted into the starting lineup. Once again, she was right — as soon as a member of the Gators’ starting five caught the flu, Horford temporarily filled in, and was never relegated to the bench again.

Horford’s professionalism with the media was also influenced by his mom

After a storied collegiate career that saw Horford win two national championships as a Gator, he was drafted No. 3 overall by the Atlanta Hawks in the 2007 NBA Draft.

Initially, Reynoso, who still resided in the Dominican Republic, didn’t plan to move to the U.S.

But, her son insisted that she needed to be nearby.

“He just told me, ‘You have to. Because if you are not around me, I think this is going to be hard,’” Reynoso said.

As such, his mother moved to Atlanta to be with her son for his first days as a pro.

“We were always so close, because I raised him alone,” Reynoso said. “That’s one of the parts that sometimes people don’t realize when you are a single mother, being all the time with your kid — the relationship built is so strong.”

Part of Reynoso’s impact on her son was furthering his appreciation of the media. She was a longtime sports reporter, and growing up, Al accompanied his mother to her work obligations and interviews — just like his son Ean follows his every footstep in the NBA.

Horford saw his mother’s frustration and disappointment when athletes refused interviews. So, he assured her that, eventually, he’d be a reporter, too. And, when he was running the show, he’d be sure to help his mom.

“When he sees somebody don’t want to give me an interview, he’d say, ‘Don’t worry, I’m going to be a journalist and I’m going to be your producer,’” she recalled.

Horford did end up majoring in journalism at the University of Florida. And, though he’s certainly not a member of the media now, he’s always made himself available to answer questions and treated the press with the utmost respect.

Reynoso said he was raised to understand that reporters help tell the story of athletes, as well as bring more attention to the sport.

“He always saw how hard it is, working in sports — for women, especially,” Reynoso tells me. “For us, it’s not easy.”

Horford promised his mom he would finish his journalism degree after his basketball career ended. Today, he’s the highest-paid Latin American basketball player of all time.

But, Mom still wants him to get that college diploma: “Life doesn’t mean, ‘Oh, I have the money. I don’t have to do anything.”

Al’s mom thinks her son has plenty of basketball ahead

Arelis Reynoso insists that no mother was as happy as she was when the Celtics finally hoisted the championship trophy.

“For four nights, Noa, I can’t sleep,” she recalled. “I forgot to sleep.”

After the title run, many speculated that Horford might hang it up at 38, seemingly accomplishing the final elusive career milestone.

But, he resoundingly rejected the notion of retirement at a signing event last June: “I don’t know how that started, to be honest. I’m coming back.”

Reynoso confirmed that her son got back into his training regiment in Atlanta — where he and his family live in the offseason — just a few weeks after winning the championship. She laughed at the concept of retirement ever being on the table after the title.

In hindsight, Reynoso recognizes her son — now a likely future NBA Hall of Famer — was never normal.

“He never asked for anything,” she said. “He’d never be like, ‘Oh, I want to play video games.’ He never has the video games. He don’t know how to play — because I never purchased anything for him — just basketball. That’s his life.’”

Eventually, Reynoso knows Horford’s playing days will come to an end, but she doesn’t think that time is soon.

“I think he’s not ready to say, ‘Oh, I don’t want to play anymore.’ I think he can keep going. And I think it’s great, and it’s special for the league, for everybody who really loves basketball — because his spirit and the vibe he has inspired too many players. He’s not done. There’s too many good things upcoming.”

This article is part of a series of stories celebrating the mothers of Celtics players for International Women’s History Month. Check out the story about Celtics second-year forward Jordan Walsh and his mother, Sandra.