When McDonald's founder Ray Kroc bought the San Diego Padres in 1974, it was only logical that a promotional tie-in between the two was only a matter of time. And on July 30, 1974, these were given to the attendees of the Padres' game against the Dodgers:
Inside the baseball were five circular Padres player cards, one that featured Ronald McDonald and a card that featured the team's home schedule on one side and the dates the rest of the team cards would be available at local McDonald's restaurants.
There was a hinge at the bottom of the baseball which allowed the cards to stay in order despite the circular design of the baseball. A hinge was placed at the bottom of each card to keep them in place...which can be seen on the Willie McCovey card below:
The set was a test to gauge a wider release in other area, but evidently it wasn't a success. No other teams were given a similar McDonald's treatment.