Posted By:
Dave ReyFrequency of perfect games in baseball history (roughly) = 1 per 31,873 regular season games.
That was figured by dividing the approximate number of games played by both leagues since 1901 (using a rough figuring) -- 478,092 games -- by the number of perfect games since 1901 -- 15.
Number of WS games played thus far in MLB history is 592.
If you assume that the historically-established likelihood of a pitcher achieving a perfect game are the same during a World Series game as they are during the regular season game, then we should see a perfect game in the WS again sometime about 5,284 years from now -- by the math...
Of course, next year five guys could, theoretically, throw perfect games, changing the math completely... In fact, just one person throwing a perfect game next year would have large impact on the math.