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The use of suspended games in MLB has changed over time.[a] Originally, all games were played to completion, unless they were halted by external conditions such as darkness or weather. Halted games that had not yet progressed to the point of being an official game were replayed (from the beginning) at a later date, regardless of the score. Halted games that had become official games either had a winner declared, or in the case of ties were replayed (also from the beginning) at a later date. Since World War II, suspended games have been used, for varying reasons depending on league rules of an era, to avoid having to replay games from the beginning.

Prior to World War II, the only instances of suspended games in MLB were games that were successfully protested, and then resumed from the point of protest.[5][7]

The first instance of a curfew-related suspended game occurred in 1943, and the first instance of a darkness-related suspended game occurred in 1952.[5] Curfew and darkness remained the primary causes of suspended games through the 1970s.[5] Since then, games have rarely been suspended for those reasons: the most recent suspension due to curfew occurred in 1998, and for darkness in 1987.[5] Every instance of a game suspended due to darkness in the 1970s and 1980s occurred at Wrigley Field, which did not have field lighting until 1988.[5]

Since 1990, weather has been the primary cause of suspended games, in situations where an official game is tied at the point that play is halted.[5]

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Halted games that had not yet progressed to the point of being an official game were replayed (from the beginning) at a later date, regardless of the score.

Prior to the 2020 season, if a regular season game was terminated early before becoming official, the results up to the point of the termination did not count and the game was started over at a later date. But as part of MLB's health and safety protocols during the COVID-19 pandemic, all games cut short before becoming official were resumed at a later date, rather than started over from scratch, during the 2020 campaign. This matched the rules that have been in place since 2008 for all postseason games and any tiebreaker games added to the end of the regular season.