Until 1965, there was no league-wide national television package for regular-season Major League Baseball games.
Teams, if they so desired, could sell rights to the networks.
Prior to 1965, network regular-season MLB telecasts had to be blacked-out in MLB cities. By 1964, thanks to expansion, network regular-season MLB games were shut-out of most major markets.
The first-ever MLB league-wide regular-season network TV deal was in 1965 with ABC. For the first time, weekend afternoon MLB games could be broadcast into MLB cities. However, network "Games Of The Week", until the late 1980's, could not be seen in the two cities whose local teams were playing in the "GOTW". From 1965 until the late 1980's, networks would cover two Saturday-afternoon games each week: One that went to most of the network (a "primary game"), and the second only being seen in the home areas of the two teams playing in the network's "primary" game. Although the "primary" game would not be televised in the home markets of the two teams playing in that game, local TV rightsholders in those cities were free to broadcast that game.
How this would work: If a network's two Saturday-afternoon "Games Of The Week" were New York Yankees at Boston (primary game) and St. Louis Cardinals at Chicago Cubs (secondary game), the Yankees/Boston game would be seen everywhere except in New York, Boston, and possibly markets adjacant to New York and Boston. Those markets got the St. Louis/Cubs game instead.
The 1965 ABC/MLB deal was only for that one season because a separate MLB deal with NBC for the All-Star Game and World Series (there were as yet no playoffs; the two teams atop their respective leages at the end of the regular-season went right into the 'Series) also ended after the 1965 season. MLB wanted to offer the "Game Of The Week", the All-Star Game and the World Series into a single package, which NBC picked-up starting in 1966.
