Complex sentence: Starting with the 2012 season, there will be two Wild Card winners in each league, who will play a single-game playoff to determine who will face the top-seeded team in the National League Division Series.
Split into simpler sentences: Starting with the 2012 season, there will be two Wild Card winners in each league. The qualifiers will play a single-game playoff to determine who will face the top-seeded team in the National League Division Series.