In baseball or softball, a starting pitcher, often abbreviated as starter, is the pitcher who pitches the first pitch to the first batter of a game. A pitcher who enters the game after the first pitch of the game is a relief pitcher.
A manager of a baseball team would like the starting pitcher to pitch as many innings as possible in a game. Most regular starting pitchers pitch for at least five innings on a regular basis, and if they are unable to do so, there is a high probability they will be moved to the bullpen. In modern baseball, starting pitchers are rarely expected to pitch for more than 7 or 8 innings, when games are passed to set-up pitchers and closers. Oftentimes, starting pitchers are on a pitch count, meaning the manager will seek to remove them from the game once they have thrown a specific number of pitches. The most common pitch count for modern pitchers is 100. Pitch counts are especially common for starting pitchers who are recovering from injury. In the early decades of baseball, it was not uncommon for a starting pitcher to accumulate an incredible number of innings—often 300 or more. In addition, there are accounts of starting pitchers pitching on consecutive days, or even in both games of a doubleheader. It is speculated that these feats were possible because pitchers in the early years of the 20th century, unlike modern starters, rarely threw the ball with maximum effort.
A starting pitcher must complete five innings of work in order to qualify for a win in a game he starts. However, it is possible to be credited with a loss despite pitching fewer than five innings. A starter who works six or more innings while giving up three or fewer runs is said to have achieved a quality start.
A starting pitcher in professional baseball usually rests three or four days after pitching a game before pitching another. Therefore, most professional baseball teams have four or five starting pitchers on their roster. These pitchers, and the sequence in which they pitch is known as the rotation. In modern baseball, a five-man rotation is most common.
Well-known starting pitchers that are currently active in MLB include veterans Greg Maddux, Curt Schilling, John Smoltz, Roger Clemens, Randy Johnson, David Wells, Tom Glavine and Pedro Martínez, and such rising stars as Johan Santana, Dontrelle Willis, Josh Beckett, Barry Zito, Roy Halladay, Kerry Wood, Jon Garland, Erik Bedard, and Chien-Ming Wang.