:(moving your answer here to keep the dialogue in one place) 
 :Any changes would probably be best discussed at infoboxes talk page, but in regards to changing the formats of the date i'd prefer we just left it the US style. Although there are players from Cuba, Japan, etc, Major League Baseball is still a US-based league so I believe the mdy format would be best used. Others may disagree though.  

 ::Allright, the MLB infobox is obviously US-based, missed that. Still think it serves no purpose to have separate fields, but it would also be pointless now to change it, as it needs no such flexibility. 
 ::But the infobox needs to comply with WP:Copyedit. The commas are not optional, at least that's my impression. 
 ::