MLB reportedly putting an end to personalized bat decals

Is the MLB going the way of the NFL to take personal touches out of the game? 

The baseball league has issued a new rule that will ban personalized decals on the knobs of bats, according to multiple reports: 

Some speculate that this new edict may be a result of corporate sponsors. 

Whatever the reason, this new rule would mean the end of San Francisco Giants third baseman Matt Duffy's fun Duffman: 

R.I.P., Duffman. 

And Mets pitcher Matt Harvey's brooding Dark Knight signifiers:

The Mets bat would allowed. The Dark Knight decals; not so much.