A relief pitcher in baseball is a player who comes into a game as a replacement for another pitcher. The first pitcher for a team in a game is known as the starting pitcher. When that player is replaced as the pitcher for any reason, such as fatigue, poor performance or strategy, the player who pitches next is a relief pitcher. A team can have multiple relief pitchers in a game, if necessary. Relief pitchers also might be called relievers. A relief pitcher whose main role is to pitch at the end of games — usually just the final inning — is often called a closer.
Saving Pitchers' Arms
When contracts for professional athletes began growing and players became commodities in the sports business, baseball managers sought ways to preserve their pitchers’ arms and prevent injuries. Decades ago, a starting pitcher in the major leagues typically would pitch until the game was over, or close to it. In modern times, however, starting pitchers rarely throw complete games and are instead replaced by relief pitchers. A pitching change might be made after a predetermined number of innings, a predetermined number of pitches, when the pitcher's performance level drops or at any other time when the manager believes that a relief pitcher might be more effective.
A relief pitcher comes into the game with a fresh arm, often as a replacement for a pitcher who was fatigued. This can help preserve the previous pitcher’s arm to prevent injury or reduce the recovery time that the pitcher needs before being able to pitch again. Most starting pitchers, for example, need about four days of rest between starts. Some starting pitchers occasionally pitch on three days' rest, but this has become increasingly rare. Relief pitchers typically pitch fewer innings each time they appear in games, so they often need less rest than starters, but they do need occasional days off as well.
The Role of Strategy
Strategy also can play a role in determining when a relief pitcher enters a game. Some managers will know that a particular batter struggles against a certain pitcher or type of pitcher and might use a reliever to get a better matchup. Many times, a right- or left-handed relief pitcher will be used against a certain batter who might hit poorly against one or the other.
Types of Relievers
There generally are two types of relief pitchers: middle relievers and closers. A middle reliever comes into the game to replace the starting pitcher or another relief pitcher, usually at some point in the second half of the game. Some middle relievers might be referred to as long relievers because they are asked to pitch for as long as possible after entering games. A long reliever might be needed as early as the first inning to replace a starting pitcher who performed poorly or was injured.
Some relievers specialize in late-game situations. The closer typically is the team's best relief pitcher and usually pitches only the final inning or two when the team has a narrow lead and wants to finish off a victory. A middle reliever whose specialty is to precede the closer by pitching the next-to-last inning is often referred to as a setup man.