MLB Bat rules and Reg.

MLB ruling for a legal wood bat

(a) The bat shall be a smooth, round stick not more than 2.61 inches in diameter at the thickest part and not more than 42 inches in length. The bat shall be one piece of solid wood.
NOTE: No laminated or experimental bats shall be used in a professional game (either championship season or exhibition games) until the manufacturer has secured approval from the Rules Committee of his design and methods of manufacture.
(b) Cupped Bats. An indentation in the end of the bat up to one inch in depth is permitted and may be no wider than two inches and no less than one inch in diameter. The indentation must be curved with no foreign substance added.
(c) The bat handle, for not more than 18 inches from its end, may be covered or treated with any material or substance to improve the grip. Any such material or substance, which extends past the 18 inch limitation, shall cause the bat to be removed from the game.
NOTE: If the umpire discovers that the bat does not conform to (c) above until a time during or after which the bat has been used in play, it shall not be grounds for declaring the batter out, or ejected from the game.
(d) No colored bat may be used in a professional game unless approved by the Rules Committee.MLB Maple bat controversy

In 2009, MLB conducted a study due to the amount of broken Maple bats.  After 6 months of research done by wood professionals and scientists, they concluded that Maple bats were breaking because Maple is a Diffuse-porous wood and that maple bats would be stronger if contact was made on the face grain instead of the end grain.  The study did not recommend any changes to Ash bats.

The results of this study have led to controversy among players and Maple bat companies.  Many players believe the study should have involved testing from actual contact by players as opposed to in a laboratory.  Also the players can hold the bat however they want regardless of where the logo is located on the bat, regardless of the conclusions of the study.

Please check out the links about the new regulations and articles from very frustrated maple bat producers.

LaCasse Bat's opinion

As far as putting the logo on the end grain instead of the face grain, only time will tell whether this catches on, or players may have to swing a bat with the logo on the end grain, but players can decide how they hold the bat.  Clearly Maple is strong regardless of where you put the logo, so the biggest factor is still where the ball contacts the bat.   This could be a controversial study, but one thing for sure is that bats will continue to break.