The switch in formats is pegged to the beginning of new national television contracts and is aimed at trying to bolster sagging World Series ratings.
"Starting the World Series in the middle of the week, when television viewership is historically higher, will provide more fans with the opportunity to watch the games," said Bob DuPuy, MLB's president and chief operating officer. "The additional off-days throughout the postseason will give us greater flexibility to facilitate travel and protect against poor weather."
In the best-of-five-game Division Series, the new postseason schedule allows for a travel day between Games 4 and 5, if necessary. Previously, in the current 2-2-1 format, if a team tied the series in Game 4, both clubs were forced to travel and play the next day in the city that hosted the first two games.
The start of the first round has been pushed back at least a day this postseason, with three of the four Division Series beginning on Wednesday, Oct. 3, and a National League Division Series starting on Thursday, Oct. 4.
Additionally, the extra off-days before the start of the World Series allows for some flexibility if games are rained out during the League Championship Series.
Last year, in the National League Championship Series, the Mets and Cardinals lost travel days on both ends because Game 1 was postponed in New York and Game 5 was washed out in St. Louis.
This year, the NLCS could end with Game 7 on Saturday, Oct. 20, and the American League Championship Series could finish up a day later.
At the other end of the spectrum, a sweep in the NLCS, ending on Oct. 15, would leave a nine-day wait for the National League pennant winners before the start of the World Series. An Oct. 16 sweep in the ALCS would give the American League pennant winner an eight-day recess.
The schedule was certainly much more compact in 1984, when there were only two postseason rounds. In the final year the LCS was decided in the best-of-five format, that year's five-game World Series between the Padres and Tigers began on Oct. 9 in San Diego and ended with a Tigers victory in Detroit on Oct. 14.
MLB staged the World Series only until 1968. With expansion in 1969, both leagues were split into separate divisions and the best-of-five game LCS was introduced. In 1985, the LCS went to its current best-of-seven format and the World Series was pushed back to a Saturday start.
In 1994, the leagues split into three divisions and the Wild Cards spots were instituted. But because a strike canceled that postseason, the LCS and the three-tier playoff format wasn't introduced until 1995.