(a) A regulation game consists of nine innings, unless extended because of a tie score, or shortened (1) because the home team needs none of its half of the ninth inning or only a fraction of it, or (2) because the umpire-in-chief calls the game.
EXCEPTION: National Association leagues may adopt a rule providing that one or both games of a doubleheader shall be seven innings in length. In such games, any of these rules applying to the ninth inning shall apply to the seventh inning.
(b) If the score is tied after nine completed innings play shall continue until (1) the visiting team has scored more total runs than the home team at the end of a completed inning, or (2) the home team scores the winning run in an uncompleted inning.
(c) If a game is called, it is a regulation game:
(1) If five innings have been completed;
(2) If the home team has scored more runs in four or four and a fraction half innings than the visiting team has scored in five completed half-innings;
(3) If the home team scores one or more runs in its half of the fifth inning to tie the score.
(d) If a regulation game is called with the score tied, it shall become a suspended game. See Rule 4.12.
(e) If a game is called before it has become a regulation game, the umpire-in-chief shall declare it “No Game.”
(f) A League President may determine whether rain checks will be honored for any regulation or suspended game that has progressed to or beyond a point of play described in 4.10(c).
Rule 4.10 Comment: The Major Leagues have determined that Rules 4.10(c) and 4.10(e) do not apply to any Division Series, League Championship Series or World Series games or for any additional Major League championship season game played to break a tie.
Game 5 of the 2008 World Series was suspended at the end of 5-1/2 innings with the score tied 2-2.
Game tied in the 9th inning is suspended due to weather.
Game completed in bottom of 7th with 2 outs and home team behind by 3
Game canceled in top of 3rd "No game."