The bottom line is... they're going to vote somebody off the island after every other race or so.
http://www.stltoday.com/sports/motor-sports/winning-all-that-matters-as-nascar-makes-move/article_4449d39a-2c58-5699-949b-4b25c71246a3.html
The field, expanded from 12 to 16 drivers, will be whittled down to a final four through eliminations after every three races of the 10-race Chase. The remaining four drivers will go into the season finale with an equal chance to win the championship: The first of the four to cross the finish line will be crowned Sprint Cup champion.
http://www.stltoday.com/sports/motor-sports/winning-all-that-matters-as-nascar-makes-move/article_4449d39a-2c58-5699-949b-4b25c71246a3.html