He had seen fans show extreme passion for a sport on his many trips to the Philippines. Last year he raved how the country began to embrace basketball.
But it was nothing compared to what he saw this week while strolling the beaches in Brazil.
"I walked on the beach [Thursday] and I've never seen so many soccer balls … in my life," Spoelstra said. "I've never seen it. I saw amazing plays, kids out there playing volleyball with their feet. It's really amazing."
The challenge of the Heat and the rest of the NBA is somehow helping basketball put a small dent in the country's soccer passion. A preseason game between the Heat and the Cleveland Cavaliers on Saturday at HSBC Arena is a start, but the league has a long way before it can think of gaining ground on soccer. What better way to begin the movement by lucking into hosting Cavs star LeBron James's first game against his former team?
"Hopefully this can help build interest in basketball, but obviously soccer is No. 1 and you can see why," Spoelstra said. "It's an incredible passion for it."
This city never expected it would be the center of the basketball universe for one night. After all, it was still soaring from hosting the World Cup over the summer. When the Heat-Cavs game was scheduled back in April, it was an exhibition matchup between a perennial power and bottom-feeder.
All that changed when James decided to leave the Heat and return to his home state of Ohio.
Suddenly, the game had appeal.
"It was a very, very, very happy coincidence that the game was set up before [James] moved back to Cleveland,' said Everaldo Marques, a former member of the Brazilian national basketball team. "It's too bad that it's just a preseason game. Then it'd be really something."
The game is already sold out. For a week, basketball has been king. The goal is for the passion to remain. Marques thinks it can happen long as the NBA continues to reach out to global audiences. Like most, he grew up playing soccer.
It changed when he followed his father, a basketball referee, to work one day.
"Everybody here at some point played soccer," Marques said. "I was too tall, too goofy to play soccer. I went to a game my dad was officiating in 1969 and I just fell in love."
Marques learned the game well enough to earn a scholarship to Kansas State. He now covers basketball for ESPN as a broadcast analyst. Stories as such are becoming more common in soccer-traditional areas. The first sport Heat forward Luol Deng played was soccer. Deng was so entrenched in the sport he refers to it as "futbol" instead of soccer.
"Every kid wants to be a futbol star," said Deng, who is from Sudan. "In the U.S., they grow up and it's American football, basketball and baseball. Here futbol dominates, so it's very hard to get kids to look at other sports. Most of the times, you play the sport that your friends are playing growing up."
It's hard to find a game of basketball around the Brazilian capital city. Soccer fields dominate the landscape. A perfect example was where the Heat practiced during the week. They worked out in a run-down gym while just a few feet away — in the same athletic complex — stood a pair of state-of-art soccer facilities.
"We're right across the street from the beach, and you can see everybody playing the tennis thing," Heat center Chris Bosh said. "They're playing soccer over the volleyball net, playing the soccer in the sand, playing soccer in the grass, soccer on the turf. Everybody loves soccer here."
It makes it even tougher for basketball to succeed with volleyball also having a strong presence. The Heat will likely lose a few viewers Saturday night because the Brazilian women's national team is competing in the World Championships in Turkey.
"When I was growing up, basketball was something like a second sport we played," said Jose Robato Lux, who has coached basketball in Brazil at various levels. "… But it's growing. Last year we had the Washington Wizards and Chicago Bulls here [for the fisrt NBA game in Brazil]. It was great. Everybody liked it. We had a full arena. We just need more games here. For sure, this year's will be bigger because of LeBron."
Added long-time Brazilian basketball announcer Alvaro Jose, "This is the best thing that could happen. For me, it's incredible because I remember the 1980s when nobody knew about the NBA."
The tandem of James and Brazilian native Anderson Varejao should leave a lasting impact on the city. Still, it's an uphill battle. This week, a Nike store in downtown had no James apparel despite the company's biggest draw being in town.
The hot-seller, naturally, was Brazilian soccer star Neymar's No. 10 jersey.
"It's a very similar situation to what's going on with futbol in the U.S.," Deng said. "It's gotten better over the years. Eventually, it's going to get there. It just won't happen overnight."