The MLB will expand its postseason to 10 teams in 2012, with each league adding an additional Wild Card winner.
Under the new format, the three division winners will remain intact, while two other Wild Card teams will qualify for a one game elimination series, with the winner advancing to the Division Series.
Beginning with the Division Series, the MLB will resume it's traditional format. One change to the format that may be needed for this season, however, is the site of the first two games in the Division Series. The winner of the Wild Card elimination game may actually host the first two games of the Division Series, before returning to the division winner's city for the final three games of the best-of-five series, a source told SB Nation's Amy K. Nelson. The switch from the traditional 2-2-1 format, in which the series starts at the division winner's home stadium, is driven by travel restraints that arise because the MLB had already determined its regular season schedule before the postseason format change was agreed upon. The MLB will adjust its regular season schedules going forward.