Philadelphia ? In a radical new incursion of advertising into professional sports, 15 teams in major league baseball will decorate bases, rubbers on the pitching mounds, and on-deck circles with spider-web designs to promote the movie “Spider-Man 2.”

In the deal between baseball and Sony Pictures, which affects only games played June 11-13, “on-field branding elements” bearing the Spider-Man movie logo will be supplemented by giveaways, including Spider-Man foam fingers.

Fans also will be shown the movie trailer on video boards at stadiums. Toronto’s SkyDome is planning a sleepover night.

“Over the past year and a half, we’ve been doing substantial research to determine the best ways to market the game into the 21st century,” said Jacqueline Parks, senior vice president of marketing and advertising for major league baseball.

“One of the clear things that came out of the research was that we have a huge opportunity with kids.”

In a coordinated effort that will include all games during the weekend, Sony will “garner 35 million impressions,” Parks said.

The league would not discuss the value of the deal, saying most of the money would be paid to it directly and distributed evenly to all 30 teams, even those not having home games.

The webbing of baseball’s diamonds is the latest commercial creep into a sport that, while never resistant to the allure of commerce, until now has kept it off the base paths.

Last year, the Red Sox sold advertising on Fenway Park’s famed left-field wall, known as the Green Monster, for the first time since 1947.

When the Yankees and Devil Rays played the season’s opening series in Tokyo, players for both teams wore 3-by-3-inch patches on their sleeves, and a logo on batting helmets, for Ricoh, a Tokyo-based photocopier company. Ricoh paid more than $10 million.