By Larry Fine

NEW YORK (Reuters) - The first taste of interleague play in 2011 comes this weekend to Major League Baseball and 15 seasons after it was first introduced during the regular season some of the match-ups still create a buzz.

Metropolitan areas that are home to two MLB teams, like New York, Chicago, Los Angeles and the San Francisco Bay area, have natural rivalries that stir fan interest.

"It's fun," New York Mets outfielder Carlos Beltran told reporters at Yankee Stadium before Friday's game against their crosstown rivals.

"It's always fun when you have the opportunity to play interleague games against teams you don't see throughout the year. I think the fans get the most out of it."

Regional competition also brings together bragging rights competition such as between the St Louis Cardinals and Kansas City Royals, who are linked by the I-70 interstate highway across Missouri.

Match-ups can also harken back to older days, such as the series being played this weekend between the Cardinals and the Orioles in Baltimore.

It will mark the first time the Cardinals will play in Baltimore and be the road team against the Orioles since the two teams shared one city, before the St. Louis Browns moved to Baltimore in 1954.

Another historical oddity brings the Chicago Cubs to the Boston Red Sox's Fenway Park for the first time since the 1918 World Series.

The last time they met at Fenway Park, Boston took advantage of right fielder Max Flack's two-run error in Game Six and clinched what would be their last title until 2004.

Mets dynamic shortstop Jose Reyes said the so-called Subway Series between New York teams never gets old.

"It's always fun every time you come here to Yankee Stadium," he said. "You know the history of this ballpark, that team there. It's always going to be exciting, the way the fans are going to be in the stadium is something unbelievable."

There will be 252 interleague games played in two segments this season -- the first one this weekend and the second from June 17-July 3.

Since its inception in 1997, regular season games between teams from the American and National leagues have been good business.

Interleague play drew 8,379,834 fans in 2010, averaging 33,253 per game, nearly 12 percent better than the usual regular season games.

The American League posted a 134-118 record against National League teams last season, the seventh consecutive year in which they held the edge in the season series.

Mets closer Francisco Rodriguez, no stranger to pitching against the Yankees during his seasons with the American League's LA Angels, said he did not view the Subway Series as something special.

"Not really. It's another series, nothing special," he said. "But not to our fans.

"The Mets fans want us to beat the Yankees, and the opposite is true, too. They want the Yankees to beat us," Rodriguez said, before betraying some added interest.

"In this case, it's going to be us beating them."

(Editing by Greg Stutchbury)