The new regulations are part of Major League Baseball's initiative to stop maple bats from breaking and flying dangerously in the air.
As part of the new rules, restrictions have been placed on the density of sugar maple that can be used to manufacture Minor League bats. Also, bats made out of several types of maple -- specifically the not commonly used silver maple, and red maple bats -- will be completely eliminated by the 30-plus companies approved to make bats, meaning the bat makers must use North American sugar maple.
The regulations will apply only to Minor Leaguers not currently on 40-man rosters and without any Major League experience. Thus the rule does not require the approval of the Major League Baseball Players' Association.
MLB and the union have been studying the issue of broken maple bats since 2008, after splintering became a problem for the thin maple bats known for their big barrels and thin handles.
More than 2,200 bats broken in the Majors during the final 2 1/2 months of the 2008 season were studied and cataloged, as well as every cracked bat in the big leagues from last year, Dan Halem, MLB's senior vice president and general counsel for labor, told The AP.
Last season, guidelines were put into effect to govern the quality of wood grain in maple bats, and as a result, they cracked about one-third less often, according to Halem. Halem added that although ash bats crack at the same rate, maple bats are more prone to breaking into multiple pieces, which can cause dangerous results. The same study also found that the breaks also relate to the grain of the wood and the weight of the bat.
Also as part of this season's guidelines, any Major Leaguer whose bat broke in two more than 10 times last year must consult with a panel of MLB and union bat experts to determine if there are further problems. A two-piece break is categorized as one where the barrel completely separates from the handle.
Baseball is also changing the specifications for all bats. The maximum diameter of the barrel will be changed, from 2.75 inches to 2.61 inches, and the minimum size of bat handles will be increased about 1/50th of an inch.
The changes are not expected have any effect on the bats that currently are being used.
"We're not taking the bat out of anyone's hands," union lawyer Bob Lenaghan told The AP.
Rhett Bollinger is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.