Professional Baseball Logo from the 1970 All Star Game AL Media Guide

It seems that for a while from 1969 to at least 1970, the familiar Major League Baseball logo included the notation "Professional" instead of "Major League" Baseball:

I first spotted this logo on a 1969 Padres program last week



and have now found another version on the back of the 1970 American League All Star Game Media Guide:


This gives us two publications from two different years which used the term "Professional" instead of "Major League". If anyone has any information on why "Professional" was used for a period of time instead of "Major League", I'd appreciate hearing from you.

For the 1970 All Star Game Fan Ballot, the MLB logo was used, and the copyright under the logo reads Major League Baseball Properties:


so why the "Professional" logo on the back of the All Star Game Media Guide?

I could see "Professional" being used in the context of covering both Major and Minor League Baseball combined, but the examples of the logo being used are on publications that are specific to the Major Leagues. I'm wondering if Professional and Major League were used interchangeably, or whether there is any significance associated with using one instead of the other.

If the design of the AL Media (Facts and Figures) Guide looks familiar, its because its the same design that was used on the 1969 Royals program


except that in 1970 the Brewers replaced the Pilots and moved the Twins, Yankees, and A's over one hour on the clock dial to keep the teams in alphabetical order by city.