Ivan Valencia knows exactly what he wants to do.

“I want to pursue a professional soccer career,” the 18-year-old said. “I know I have the potential. I feel I’ve been a top player on every team I’ve played on.”

A few years ago such a bold statement, from a San Leandro teen whose family has limited economic resources, would be a far-fetched dream. But for Valencia, one of the top players in the Earthquakes Academy Under-19 program, it’s a real goal. He hopes to sign a professional contract in the coming months.

There’s a quiet revolution going on in the Bay Area, an offshoot of a bigger one that will likely change the way the world’s most popular sport is played by Americans. One that should help the fortunes of the U.S. men’s national soccer team in its goal to become a world power. And one that allows talented players like Valencia — who might have been shut out of previous pathways due to finances — a realistic path to professional soccer.

The San Jose Earthquakes, like other MLS teams, have established a training academy. What was a small-scale, lightly funded operation in 2012 when Chris Leitch took over as the team’s technical director has been built into a deep developmental system, with six age-specific boys teams from U-12 to U-19, that include several players who are playing in the U.S. national youth programs. This year, the Earthquakes became a member of the U.S. Soccer Girls’ Development Academy, with four age-specific girls’ teams, from U-14 to U-19.

“We are looking at how it’s done in the rest of the world,” said Leitch, who became the head coach of the senior Earthquakes team in June, replacing Dominic Kinnear. “We want to get players into the developmental pathway when they’re young and take them to the highest level.”

Historically, the Earthquakes have signed only two homegrown players, but that will be changing as players who have spent four or five years in the academy are coming of age. The Earthquakes retain the MLS rights to their academy players. Some, like Valencia, a five-year academy member, hope to go pro immediately. Valencia will spend a week with the Earthquakes’ lower division affiliate in Reno and hopes to sign a contract soon.

Others, like goalkeeper JT Marcinkowski, are taking a more conventional American path. The player from Alamo is entering his junior year at Georgetown. But he knows he is more prepared — for the college game, a professional career, and for a role in the national program — thanks to his academy experience.

“I don’t know if people can understand what a difference it makes,” said Marcinkowski, who was on the U.S. roster for the U-20 World Cup last spring. “The academy program will help us make bounds and leaps in the success of the U.S. national team and MLS as a league.”

College soccer used to serve as an academy of sorts for MLS, with many players turning pro after their college careers. Leitch was one of them, growing up in rural Ohio, learning the game from the few foreigners available to coach soccer in his area, then playing collegiately at North Carolina. When he was drafted by MLS in 2001, he was a 22-year old rookie with a lot to learn.

“I realized a lot of my training was missing,” he said.

In other countries, the top soccer clubs have academies that promote vertical development. Promising young players are invited to join an academy and learn to play the game the right way as they develop. By the time they are 22, they are hitting their prime.

That’s the kind of system MLS is trying to emulate. Earthquakes general manager Jesse Fioranelli joined the team in January from AS Roma, a team in Italy’s top league, Serie A. His charge is to rebuild the Earthquakes’ system for the future. The upheaval in the coaching staff was part of that process.

In 2013, Leitch was part of an MLS delegation that went to the French Football Federation’s training program for 16 months. He received his Elite Formation Coaching License at the program in Clairefontaine, France’s national training center. He received instruction on the field, in the classroom and through visits to Real Madrid and Porto. He and other MLS coaches, who visited other elite European clubs, shared what they learned.

“These clubs have a structure, a vertically integrated path from early age to the top level,” Leitch said.

Hanging in Fioranelli’s office in San Jose is a painting of Andres Iniesta, the brilliant midfielder from FC Barcelona. The Barcelona system is the world’s most renowned: a style and process taught at every level, from the youngest academy members to the senior La Liga team. It is a style that helped create Lionel Messi, who joined Barcelona as a teenager, and that helped Spain win a World Cup.

“Barcelona represents the strongest identity,” Fioranelli said. “We want a club culture. So that a 12-year-old has a feeling he belongs with something.”

Valencia is excited to be a part of that.

“I think it’s definitely realistic,” said the attacking midfielder, whose favorite player is Messi. “They’re trying to create that kind of culture. It just takes time.”

Part of the infrastructure that Earthquakes owner John Fisher has invested in includes a full-time scout. Valencia was found playing for the Tecos, a youth team in Hayward, when he was 14, and invited to a tournament in Portland. Top players from all over Northern California are invited for tryouts. Some academy players travel from as far away as Fresno four times a week.

Once a player makes the academy team, there is no charge. That is a huge factor in advancing the development of American soccer, which has been dominated for years by a pay-to-play system with elite youth clubs. That system has, too often, left out talented players from financially struggling families.

“I don’t think I’d be playing if I had to pay to play,” Valencia said. “That’s one reason I want to pursue soccer, to help my family.”

Marcinkowski played for one of those elite clubs, Mustangs soccer in Danville, before joining the Earthquakes’ academy. He sees the difference.

“You get to be on the team because you’re good enough, not because you have the money to play,” he said. “There are no sections within the team. You’re there because you’re good.”

The academy emphasis is on playing the game the right way, not winning at all costs.

“They focus a lot on the small details, how you receive the ball, how you place yourself,” Valencia said. “It prepares you for the next level.”

The academy also emphasizes developing professional, mature individuals. The academy checks on players’ grades. Coaches demand a level of commitment. Leitch said Valencia was shy and introverted when he arrived. Now he is a confident, assertive young man who occasionally gets to train with the senior team.

“I look like I belong,” he said. “I think I’m not that far. The main difference is physical maturity.”

The Earthquakes’ system will produce only a handful of pro prospects each year, at most. The investment is seen as being worth it financially to the club, which won’t have to spend millions in the future to buy top players. Leitch and Fioranelli also say they are investing in a culture and in young players, who will help build a brand, a loyalty and a lasting system.

“We are trying to provide a tangible, visible pathway,” Leitch said. “We are creating a better domestic player.”

And an athletic revolution.

Ann Killion is a San Francisco Chronicle columnist. Email: akillion@sfchronicle.com Twitter: @annkillion