But walk down a street in this city of 12 million wearing a Sox cap and No. 18 jersey and it becomes apparent that the implications of the signing stretch far beyond the mound at Fenway Park.
The hat draws smiles, waves, bows, even an offer to buy it then and there.
"It is good that [Matsuzaka] was the one chosen to go to the United States," says Osato Nakamura, summing up the spirit of those in Japan. "He will be a hero there as well."
Suddenly, a simple red B stands as a symbol linking the sporting obsessions of two cultures. And that could translate to future wealth and success for the club that forged the connection.
American fans may question multimillion-dollar investments in international stars. But teams spend the money knowing they'll be rewarded with more than on-field brilliance.
By signing Matsuzaka, the Red Sox established a greater profile in their sport's hottest new talent market. By signing David Beckham to a $250 million package of salary and endorsements, the often overlooked Major League Soccer gained the implicit endorsement of one of the world's most famous people. By drafting Yao Ming, the Houston Rockets forged a flesh-and-blood link between the NBA and an exploding market of 1.3 billion potential basketball fans.
"If done properly, there's enormous upside in these deals," said Marc Ganis, a Chicago-based sports marketing consultant. "When you have players from countries like Japan, Taiwan, China, anywhere in Europe, there's such an ability to generate sponsorship and marketing deals in those countries."
Baseball stars Matsuzaka, Ichiro Suzuki and Hideki Matsui rank as national heroes based on their major league exploits. Packs of Japanese reporters follow each star around the United States and even their most mundane achievements -- say a 1-for-4 night against Tampa Bay -- become front-page news. About 250 major league games appear on Japanese television each year. Even as American fans watched Matsuzaka take on the New York Yankees on Sunday night, millions of Japanese did the same Monday morning.
Television and merchandising revenues are divided evenly among baseball's 30 clubs. So the effects of Ichiro, Matsui and Matsuzaka benefit the entire league.
The immediate economic benefits to the Red Sox may be more limited. They already sell out every game and charge more per ticket than any team in the league. They spent $103.1 million ($51.1 million for his rights and a six-year, $52 million contract) on Matsuzaka primarily because they wanted an ace for the next six years.
"It was first, second and third a baseball decision designed to give us a better team and a better rotation," Red Sox president Larry Lucchino said. "There are some ancillary benefits, but they are just that -- ancillary. The notion that there's some enormous pot of marketing gold is illusory."
The Red Sox can sell advertising space at Fenway Park to Japanese companies or to American companies targeting Japanese fans. When Matsuzaka faced Ichiro for the first time, the center-field wall featured a Dunkin' Donuts sign with a message scrawled in Japanese characters.
But Ganis said the economic benefits of owning Matsuzaka are "fractional."
"Those revenues offset the cost of a player's contract more than if he were from Alabama or the Dominican Republic," he said. "That said, the Red Sox paid so much upfront that he'll have to pitch well to make it a good deal. If he's not a top-of-the-rotation starter, they overpaid."
The greatest payoff may be abstract for now.
"I thought the purpose of the $51 million was not just to get Matsuzaka but to establish a public relations presence," said Robert Whiting, who has written several acclaimed books on Japanese baseball. "The Yankees and the [Seattle] Mariners had monopolized the attention here, but that $51 million was such a figure that it went through the country like an electric shock."
The next wave of Japanese stars will have Red Sox on the brain, he said, and if they're unwilling to sign anywhere but Boston or New York, other potential suitors may be scared away from bidding. Whiting speculated that unsigned Japanese amateurs may also be eager to try out for the Red Sox. So the investment could return talent beyond Matsuzaka's strong right arm.
Lucchino said he hopes that's the case.
"It's not something you can quantify very easily in dollars and cents," he said. "But we're looking at it as more of a long-term play. We hope to be the most popular major league team in Japan. We think there are benefits to that."
NBA hits its shot
The NBA has been even more aggressive than baseball in linking itself to overseas markets. Commissioner David Stern believed so strongly in the mission that he virtually gave away television rights in European and Asian markets so the league could broaden its presence.
As a result, the NBA has 83 international players from 37 countries, compared to 21 international players from 18 countries in 1992. European stars have raised the profile of the game so much that the league may one day be able to start an offshoot there.
China may prove the biggest catch of all. Stern first traveled there in 1990, looking to strike a television deal. He discovered a nation that already loved basketball and revered American stars such as Michael Jordan.
"But he understood that the Chinese public -- and more importantly, CCTV itself -- would never fully embrace the NBA until one of their own was playing in the league," Newsweek reporter Brook Larmer wrote in his book, Operation Yao Ming.
The 7-foot-6 center from Shanghai would be that player. His presence immediately bumped Houston's home attendance 17 percent and made the Rockets one of the league's hottest road draws. Reebok, Apple, McDonald's, Visa, Gatorade and Pepsi signed deals with the giant in hopes of tapping the Chinese market.
The league appears on 51 Chinese television stations and has accrued a viewership of 428 million this year. China accounts for 20 percent of the traffic on NBA.com, and the Rockets' Mandarin-language Web site ranks among the most viewed sports pages in the world. NBA merchandise sells in more than 20,000 Chinese stores, and the league will open 10 NBA-specific shops in the country by the end of the year.
"Yao is so important because we're talking about China at this period in history," Ganis said. "It's the second-greatest economic power in the world, and in 15 years, it's gone from a socialist country in which everyone wore uniforms to one of the world's top five consumer markets. Yao is a significant bridge to that."
Soccer kicks in
Ganis estimated that the center is worth seven figures in annual sponsorship revenues for his team, an enormous sum considering that the Rockets signed him within the league's normal salary structure.
The same can't be said for Beckham, whose mammoth deal is way out of scale for a league where many players make less than $100,000. But few doubt the Englishman will be worth it when he suits up for the Los Angeles Galaxy in July.
MLS receives scant mainstream attention in the United States, but it's suddenly on the pages of People and on the lips of Access Hollywood anchors. Children in Asia and Europe who've hardly given a second thought to U.S. soccer will wear Galaxy jerseys. If the league can attract more international stars, it might connect deeply with immigrant populations that live in the United States but live and die with soccer teams from their original countries.
"The reality is that we get not only one of the best soccer players in the world, but one of the most famous people in the world, endorsing our product on a day-to-day basis," Galaxy general manager Alexi Lalas said.
As a former world-class player, Lalas has observed the world's snobbery toward U.S. soccer for years. He thinks it's groundless and calls MLS one of the world's most competitive leagues. "But this signing gives us a certain platform to achieve credibility," he said. "That's very important because our sport is so international. Our credibility isn't just our domestic credibility as might be the case with the NFL or baseball."
Unlike most major sports leagues in the United States, MLS is a single business entity, so all clubs will benefit from extra revenues generated by Beckham.
"This sport is the language of the rest of the world, and we have to get aggressive about teaching it to the American public," said Dave Checketts, whose SCP Worldwide controls the league's Real Salt Lake franchise. "No one is better suited to do that than Beckham. No one else is even in the same league celebrity-wise."
Real Madrid was already the world's most glamorous soccer club when it signed Beckham four years ago, but officials were nonetheless stunned by the extra marketing punch he brought. They came to regard his contract of 35 million Euros as a pittance.
"Beckham's global appeal is unlimited, truly unlimited," said Jan Runau of Adidas in White Angels, English journalist John Carlin's book about Real Madrid. "The people he reaches on and off the field: No other athlete has even close to the same global impact. No one else can stop the traffic in central Tokyo. People mention Tiger Woods. Beckham is much, much bigger -- apart from anything else, because the sport he plays is the world's most popular by far."
Lalas said that during the offseason, Galaxy officials agreed that they needed to do something bold. "Regardless of your business, you're looking for a moment of truth," he said. "And I can't imagine a bigger moment of truth than signing David Beckham."
Already, season ticket sales have shot up, new sponsors have signed on and television dates have multiplied. Lalas said he can't yet put a number on Beckham's economic impact, "but it's already hit our entire business in so many ways."
The thinking behind the signing is hardly unprecedented.
In the 1970s, the New York Cosmos signed Pele and other international stars in hopes of popularizing soccer in America. The formula worked for a while as the Cosmos drew more than 40,000 fans a game at Giants Stadium and earned the North American Soccer League a television deal. But the NASL's other franchises never matched the Cosmos' aggression, and the league folded less than 10 years after Pele signed his contract.
"They signed every star," Checketts said of the Cosmos. "The other teams had no one."
Lalas argued that the audience for American soccer is broader and more established than it was 30 years ago. He also noted that MLS features more world-class American players than the NASL. That means the Galaxy will seem less like a touring carnival and more like another solid team with a new star.
"We're here to put on a show," he said. "But in a sporting context."
Candus Thomson reported from Tokyo; Childs Walker reported from Baltimore. Sun reporter Dan Connolly contributed to this article.
Coming to America
Major signings of foreign stars:
1975 -- The New York Cosmos lure Brazilian soccer legend Pele out of retirement with a three-year deal reportedly worth $7 million.
1989 -- Lithuanian Sarunas Marciulionis joins the Golden State Warriors, paving the way for a flood of European stars in the 18 years since.
1995 -- Hideo Nomo "retires" from Japanese baseball, signs as a free agent with the Los Angeles Dodgers and wins Rookie of the Year.
1997 -- The San Diego Padres purchase pitcher Hideki Irabu from his Japanese team but are forced to trade his rights to the Yankees after he declines to pitch anywhere but New York. In response, baseball creates the posting system for Japanese players.
2000 -- The Seattle Mariners pay $13 million for negotiating rights with Ichiro Suzuki, who becomes the first Japanese superstar in the majors.
2002 -- The Houston Rockets select Yao Ming first overall in the NBA draft.
2006 -- The Boston Red Sox pay a record $51.1 million for the negotiating rights to pitcher Daisuke Matsuzaka and then sign him to a $52 million deal.
2007 -- The Los Angeles Galaxy signs English soccer star David Beckham to a deal that could total $250 million, with endorsements and revenue sharing included.