In 1967, both leagues voted to add 2 more teams each, to bring the league total to 24 teams, which started in 1969. Divisional play also began, with each league dividing into East and West division, creating another round of playoff games to decide the pennant winners.

In 2020, the season was only 60 games due to the COVID-19 virus spread and protocols put in place by MLB. Because of this, the set includes more players than usual, as rosters were expanded.