There could only be a maximum of three sweeps between 1969-95, when there was a World Series and two League Championship Series, and there were no instances in that time of all three series resulting in a sweep. Division Series games were used in the strike-shortened year of 1981, but there were only two 3-0 sweeps then. Before 1969, the postseason consisted only of the World Series.
The Diamondbacks will open the National League Championship Series at home against Colorado on Thursday, and either the Indians or Yankees will start the ALCS on Friday at Boston. So one more sweep in either of those LCS or the World Series, and it will represent the most sweeps in a single postseason. Here were the other years in the DS era that resulted in three postseason sweeps:
2006: The Tigers swept four from Oakland in the ALCS, clinching it on Magglio Ordonez's walk-off homer; the A's swept the Twins in the ALDS and the Mets swept the Dodgers in the NLDS. That Detroit sweep represented only the fourth time in 42 opportunities that an LCS team swept a best-of-seven series (starting with 1985); the others were Atlanta over Cincinnati in 1995, and Oakland in both 1988 and '90.
2005: The White Sox took all four games (each barely) from Houston in the World Series; that same Chicago team had swept Boston in the ALDS, and St. Louis swept the Padres in the NLDS.
1998: One of the best Yankee teams ever swept the Padres in the World Series, just as they had done to Texas in the previous ALDS; the Braves swept the Cubs in the NLDS.
1995: Cincinnati swept the Dodgers in the NLDS, but then was swept by the Braves in the next round; and Cleveland swept Boston in the ALDS, even though Manny Ramirez went 0-for-12 against his future team.
So far, this postseason can be contrasted most vividly with the one in 2003. That was the October of almost constant walk-off, do-or-die drama, and the only time in the three-round era that there were no sweeps in any series. It could be argued that it was the October that propelled the game to another level, loaded as it was with seven tradition-rich clubs and a relative newbie (Florida) that won it all -- and leading to four consecutive years of record overall MLB attendance.
Both League Championship Series that year went to seven games, with the Marlins pulling off that shocking comeback to beat the Cubs and Aaron Boone of the Yankees hitting the homer that beat Boston. Two of the four Division Series went the distance, with Derek Lowe pitching Boston to that clincher at Oakland and Kerry Wood dominating for the Cubs at Atlanta. Even those other two DS were dramatic, typified by Pudge Rodriguez holding onto the ball in a collision at the plate to preserve that clinching Game 4 victory against the Giants.
The 2007 Yankees have just prevented this particular postseason from being remembered for a clean sweep. Now three other clubs will sit back and wait after doing everything right and leaving opposing fans wondering what hit them.