At 27, Siddhartha Sanchez of Washington Heights is a lifelong Yankees fan, but he’s feeling increasingly lonely in the neighborhood.

“You can walk into a restaurant in Washington Heights and you’re the only Yankees fan,” Mr. Sanchez said. With more and more Dominican’s rooting for the Red Sox, he said, “It’s creating a split in the community. Even more so than politics, you have splits within families.”

He spent Monday night watching the game with his godfather, who was rooting for Boston. Luckily, Mr. Sanchez left before David Ortiz’s game-winning RBI single in the 14th inning. “I didn’t want to watch him gloat,” Mr. Sanchez said.

A wealth of Dominican stars in Boston set off this steady flow of switch hitting fans over the past five years or so.

The president of Hispanics Across America, Fernando Mateo, is one of many Dominican Yankee “fans” who rooted for the Red Sox last night.

“I’m a Yankee fan because I grew up in New York and in the Bronx and I appreciate what good baseball is,” Mr. Mateo, an entrepreneur, community leader, and leading Bush supporter, said yesterday. “But I am also very close to the Hispanic ballplayer and I like Manny Ramirez, he’s a New Yorker, I like Ortiz, I like Martinez, I like what the Boston Red Sox have done with Dominican ballplayers.” Manny Ramirez, David Ortiz, and Pedro Martinez are all Red Sox stalwarts.

For Mr. Mateo and others, though, their new allegiance is more than a matter of Boston having more Dominican stars than their hometown team has. It’s also their frustration with a perceived prejudice by the Yankee organization against Dominican ballplayers.

“I don’t like the fact that they don’t support Dominican ballplayers when New York is officially the second Dominican capital,” Mr. Mateo said. “If it was the Yankees against anybody else, I’m a diehard Yankee fan, but it’s against Boston and I like what the Boston Red Sox have done with Dominican ballplayers.”

Part of the complaint among New York City’s 500,000-plus residents of Dominican descent is that with the Dominican Republic as the no. 1 exporter of baseball talent to America, the Yankees should have more than two players born in the Caribbean nation – and those two, Enrique Wilson and Felix Heredia, are among the team’s least prominent players.

In the Dominican Republic, where baseball arrived after American Marines brought it to nearby Cuba in the mid-19th century, there are all sorts of explanations of why the island nation produces more stars than much larger countries. Some say it is the legacy of the Taino Indians, the pre-Columbian civilization that played a game like baseball. Others float the notion that while other Latin American countries play soccer, it is too hot in the Caribbean and so the Dominicans turn to the more languid baseball. Whatever the reason, such stars as Albert Pujols, Vladimir Guerrero, and Miguel Tejada are among the game’s brightest.

The Yankees do have Alex Rodriguez, born in New York to Dominican immigrants but transplanted to Florida as a child. Many Dominicans in Manhattan said he started off with the Yankees on the wrong foot, however, because he was traded for Alfonso Soriano. Some fans called the move good business, but others complained that it was part of a local pattern of not cultivating Dominican talent.

Last week, in any event, A-Rod’s popularity uptown plunged. When asked if he considered himself American or Dominican first, he chose the former. “Alex Rodriguez: USA,” the Spanish language newspaper Hoy reported on the front page. “It only took three seconds and an equal number of words for him to destroy the image of hero that he had in the Dominican Republic.”

At J &J Sports Bar in Harlem last night, men wearing Boston Red Sox jerseys and caps outnumbered Yankees fans.

Robert Tavajes, 27, said he has been a Red Sox fan ever since he was an 8-year-old living in the Dominican Republic and the team came to the Caribbean nation on a training trip. Even though he now lives in New York, he has not grown fonder of the Bronx Bombers. “Yankees aren’t putting out Dominican players, even though they are very good,” Mr. Tavajes said.