Diaz emigrated from Mexico when he was 14, plays soccer with his friends at a local park and occasionally goes to watch the league's two Los Angeles-based teams, Chivas USA and the Galaxy.
"I'll go to one or two games to see how Beckham is playing," the 32-year-old Diaz said while buying a knee brace at Niky's, a soccer store in a predominantly Hispanic neighborhood. "If I see he's not into it, I'm not spending any more money."
Hispanics made up a third of fans at MLS games last season, according to league statistics, with the percentage higher in Hispanic-heavy cities such as Los Angeles and Dallas. Regular-season games averaged 15,504 fans, a tiny fraction of the tens of millions of soccer fans and players the league estimates are in the United States.
Hispanic immigrants are both a substantial MLS fan base and a relatively untapped market. The 13-team league is hoping a recent deal with Spanish-language giant Univision to broadcast some games this season will help change that.
Even with more exposure, the sell could prove difficult: Many Hispanics scorn MLS as a bush league where players show little of the panache and artistry that gives soccer its "beautiful game" name.
"Soccer here looks like a game of American football," said Juan Munguia, a 30-year-old cook from Mexico. "It's all blows but very little grace."
Los Angeles Galaxy general manager Alexi Lalas, a former U.S. national team and MLS standout, said the former England captain will attract savvy Hispanic fans by elevating the level of play. The Galaxy certainly hope so - the team promised Beckham millions of dollars more in salary than any other player as part of a five-year deal worth about $50 million.
That's an unheard of compensation package for MLS, where the average player salary was $100,000 last year and the last team to sell, D.C. United, went for $33 million a couple of weeks ago.
Lalas said Beckham speaks some Spanish after playing several years for Spain's Real Madrid, but wasn't sure whether he'd use it in commercials or team promotions. Galaxy news releases are in English and Spanish, and the team soon will launch a Spanish version of its Web site.
"David Beckham on the surface couldn't be more disassociated with the Hispanic community," said Lalas, referring to the Hollywood glitz he brings with his wife, former Spice Girl Victoria Beckham. "But the fact is this is a player who has played with some of the biggest teams in the world, including Real Madrid."
Beckham should add to the rivalry between Galaxy and Chivas USA, said Chivas USA CEO Javier Leon. The northern sister team of Mexico's popular Chivas Guadalajara team, Chivas USA joined MLS a few years ago and caters to Hispanic fans.
"Beckham now becomes a target," said Leon. "Our fans will be intrigued to watch us play him."
Rafael Ramos Villagrana, a soccer columnist for the Spanish-language newspaper La Opinion, said many Hispanic fans are turned off by the heavy marketing of Beckham.
"Some fans are saying he just came here to sell T-shirts and Pepsi Cola," said Villagrana. "But if he plays well, they'll end up falling in love with the Galaxy."
Since its founding in 1996, the MLS has tried to attract Hispanic fans, believing they were the key to building a permanent base - something the precursor North American Soccer League failed to do from 1968-1984. Today, there are more than 42 million people of Hispanic origin in the United States, about 60 percent of whom are U.S. born, according to the U.S. Census.
The league directs about 40 percent of its marketing toward Hispanics and sponsors adult tournaments nationwide that draw Hispanics, said spokesman Dan Courtemanche.
"We know there are millions of soccer fans, including millions of Hispanic fans, who are currently not MLS fans," said Courtemanche.
The huge number of Hispanic soccer fans who don't attend MLS games is most obvious when Mexican teams play matches here. When Mexico played South Korea at the Los Angeles Coliseum a year ago, more than 64,000 people attended. A doubleheader in August that featured Chivas USA versus the New England Revolution, followed by Barcelona against Chivas Guadalajara, attracted 92,650 fans.
Gabriel Gabor, an MLS consultant who focuses on the Hispanic market, believes Beckham will help close that gap.
There is "a group of hard-core soccer fans who say, 'I'm not coming out until they get a big name,'" said Gabor. "Now they'll have it."
Galaxy and league officials also believe Beckham's good looks will draw more women, Hispanic and otherwise.
"I want to see Beckham because he's hot," said Liz Galan, a 21-year-old community college student born in Los Angeles to Mexican parents. She never has attended an MLS game.
"Yeah, women are going to go and take along their husbands," giggled her friend, Monica Jimenez, 24, also a community college student born here to Mexican parents.
So far, Beckham promises to increase attendance at Galaxy games - whether the fans are Hispanic or otherwise. The Galaxy have sold several thousand season tickets since Beckham's Jan. 11 signing.
Back at Niky's soccer store, owner Niky Orellana said the buzz has been "incredible."
The store gets dozens of calls each day inquiring about Galaxy tickets, while $80 Beckham Galaxy jerseys have been selling fast.