From BR Bullpen
A suspended game is a game that is stopped while being played and completed at a later date. The rules governing suspended games have changed a number of times, most recently before the 2007 season. A number of circumstances can lead to a suspended game, the most common being a game that has gone for 4½ innings, becoming an official game, and is stopped by weather with the score tied. A regular season game that has not yet become official is simply wiped off the books, but in the postseason, such a game is suspended and will be resumed from the point at which it was interrupted.
Before the 2007 rule changes, a game stopped by weather with the scored tied after it had become an official game was called a tie and was later replayed in its entirety if the scheduled allowed or if it affected the result of the pennant race. The only exception was when the visiting team has just taken the lead before the interruption, in which case, because the home team had not had as many turns at bat as the visitors, the game was suspended until the remainder can be played. Such a circumstance still results in a suspended game under the current rule.
Another instance causing a game to be suspended is when a game is stopped by a curfew or lighting issues. For example, when Wrigley Field was the last major league stadium not to have artificial lights, a game stopped by darkness was suspended until it could be played to completion. When artificial lights were the exception rather than the rule, however, a game was only suspended if it was tied when the lack of light made it impossible to continue play; otherwise the game was called at that point.
Because there can be a significant amount of time elapsed between the start of a suspended game and the date of its completion, it can lead to strange situations in which a player is listed in playing a game taking place before his major league debut or while he was with another team (the date on which the game started is considered the game's date, and not the date at which it was completed).
 Further Reading
- Stephen D. Boren: "Anomalies of Protested and Suspended Baseball Games", The Baseball Record Journal, SABR, Volume 41, Number 2 (Fall 2012), pp. 14-20.