From BR Bullpen
A forfeit is a game which is ended by the umpire because of a severe rule violation by one team. The team in violation is automatically the loser and the other team is the winner.
 Grounds for Forfeit
According to Major League Rule 4.15, the umpire may call a forfeit when a team:
- (a) Fails to appear upon the field, or being upon the field, refuses to start play within five minutes after the umpire has called "Play" at the appointed hour for beginning the game, unless such delayed appearance is, in the umpire's judgment, unavoidable
- (b) Employs tactics palpably designed to delay or shorten the game
- (c) Refuses to continue play during a game unless the game has been suspended or terminated by the umpire
- (d) Fails to resume play, after a suspension, within one minute after the umpire has called "Play"
- (e) After warning by the umpire, willfully and persistently violates any rules of the game
- (f) Fails to obey within a reasonable time the umpire's order for removal of a player from the game
- (g) Fails to appear for the second game of a doubleheader within twenty minutes after the close of the first game unless the umpire in chief of the first game shall have extended the time of the intermission.
A game may also be forfeited if the home team fails to follow the umpire's instructions for bringing the field into proper condition after an interruption (Rule 4.16). This may be because the home team refuses to prepare the field properly after a weather delay or because it is unable to clear fans or objects from the field within a reasonable time. Finally, a team may be forced to forfeit a game if they are unwilling or unable to field a full 9 players (Rule 4.17).
Forfeit games have several interesting scoring quirks. Like other called games, players are credited with their statistics for the game if enough of the game had been played for it to count as an official game. If the team credited with the win was leading at the time of the forfeit, the pitchers are credited with a win or loss exactly as they would be in any other called game. If the forfeiting team was ahead at the time that the game was called, no pitcher is credited with a win or loss. All forfeits are officially listed as 9-0 victories for the team that benefits from the forfeit, regardless of the actual status of the game.
 Historical Forfeits
Forfeits were far more common in the early days of the game than they are today. Some seasons in the 19th Century saw 10 or more forfeits, with as many as 13 in 1884. It was routine to have several forfeits each season through the rowdy 1880s and 1890s. They remained an annual event through the Deadball Era and became less common after. Forfeits became extremely rare after World War II, with just 7 since 1945.
Most forfeits since WWII have been a result of teams' inability to control unruly fans, with the most notorious failues being 10-cent beer night in Cleveland in 1974 and Disco Demolition Night in Chicago in 1979. The most recent forfeit happenedon August 10, 1995, when Los Angeles Dodgers fans bombarded the field with souvenir baseballs to protest the ejection of Raul Mondesi and Tommy Lasorda.