There have been 12 single-game tiebreakers in MLB history. Each of them brought the nerves and anticipation of a playoff matchup, even though they were played as regular-season games -- but game No. 163 is now a thing of the past.
With an expanded playoff format launching this October, MLB decided there wasn't enough room on the calendar to break ties in that extra-game manner anymore. Instead, a set of tiebreaking rules will now decide not only seeding but also who gets into the postseason altogether if 162 games aren't enough to determine the 12-team field. This means that the series your favorite team played way back in the first half could have a huge impact on its playoff hopes.