Breaking down the gyroball

You wouldn't think a slider that doesn't break would be too valuable. But it does break, and in this game of inches, it could be just enough.

When Japanese television analysts tried to deconstruct the mystifying slider thrown by Daisuke Matsuzaka, they called it a gyroball, partly because the pitch seemed to come from another world.

Matsuzaka says he does not throw any such pitch in games — but when he signed with the Boston Red Sox this off-season for $52 million, American baseball fans were forced to confront the mystery.

Is the gyroball a myth, or is it real? And if it is real, what exactly is it?

Kazushi Tezuka says he has the answer, and he flew from Japan to the United States this week to reveal it. Tezuka, a Japanese trainer who is credited with creating the gyroball 12 years ago, walked to the mound at Scottsdale Stadium on Wednesday to show off his invention.

Tezuka used a standard fastball grip. He went into a basic motion. Only at the end of his delivery did he deviate. He turned the inside of his throwing arm away from his body and released the ball as if it were a football, making it spiral toward home plate.

The pitch started on the same course as a changeup, but it barely dipped. It looked like a slider, but it did not break. The gyroball, despite its zany name, is supposed to stay perfectly straight.

“That’s it!” Tezuka said, laughing hysterically on the mound. “That’s the gyro!”