Mattingly's new venture, called Mattingly Baseball, features a special "V-grip" on its bats, designed to help children learn the proper way to hold the bat as they begin playing the game.
After retiring from baseball in 1995, Mattingly noticed that his sons were having problems with their grip on the bat, squeezing it too tight instead of letting it rest in their fingertips. Mattingly designed the "V-grip," which features three shaved-down sides of the bat handle, to help correct those problems.
"The whole company has really evolved through that simple invention," Mattingly said. "Just trying to get kids to hold the bat the right way."
Mattingly's company is producing bats for all levels, with the new grip featured on all bats, both wood and aluminum, other than those made for the Major Leagues. Mattingly Baseball also features other equipment and apparel, including batting gloves, bags and clothing.
Mattingly hopes that some big leaguers will use his brand to increase exposure, but the growth of the company will rely on the success of the grip and its effectiveness at the youth level.
"We've grown from the simple concept of kids holding the bat properly, which starts at the Little League level and in high school," Mattingly said. "I'd rather it grow from the grass-roots level, to start from the age when kids start playing."
Mark Feinsand is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.