Baseball rules credit a win, abbreviated W, to one pitcher on the victorious team. The pitcher receiving credit is normally the pitcher of record at the time that the team takes a lead that it never relinquishes. There are two rare exceptions to this general principle:
- A starting pitcher must pitch for at least 5 innings to receive credit for a win, unless the game goes only 5 innings (in which case he must pitch at least 4) or he is pitching in an exhibition match (such as the All-Star Game) that has rules restricting the length of his appearance.
- A reliever may be denied the victory if he is "ineffective in a brief appearance".
In either exceptional case, the official scorer is allowed to determine which subsequent relief pitcher deserves credit for the victory. In practice, most official scorers will credit the pitcher who immediately follows the one denied the victory.
A relief win is a win earned by a pitcher who did not start the game. This statistic is one of those used to determine the winner of the Rolaids Relief Award.
|Records for Pitcher Wins|
|MLB Career||Cy Young||511|
|MLB Season||Charley Radbourn||59||1884|
|MLB Season (since 1900)||Jack Chesbro||41||1904|
|NPB Career||Masaichi Kaneda||400|
|NPB Season||Victor Starfin||42||1939|
|NPB Season||Kazuhisa Inao||42||1961|
|Negro Leagues Career||Bullet Joe Rogan||151|
|Negro Leagues Season||Nip Winters||27||1924|
|Minor Leagues Career||Bill Thomas||384|
|Minor Leagues Season||Stoney McGlynn||41||1906|
|Cuban National League Career||Pedro Luis Lazo||247|
|Korea Baseball Organization Career||Jin-woo Song||201||through 2006|
|Korea Baseball Organization Season||Myeong-bu Chang||30||1983|
|Italian Baseball League Career||Rolando Cretis||183|
|Italian Baseball League Season||Giuseppe Silva||21||1970|
|Hoofdklasse Career||Rob Cordemans||200||As of September 2020|
|AAGPBL Career||Helen Nicol||163|
|AAGPBL Season||Joanne Winter||33||1946|
|AAGPBL Season||Connie Wisniewski||33||1946|
Wins and losses were not compiled in the early days of Major League Baseball. Henry Chadwick began the practice of awarding pitching wins in the 1885 Spalding Guide, but this did not catch on immediately. The two main publications of the 1890s, The Sporting News and Sporting Life used different criteria to attribute wins, an issue which only became more complex as the use of relief pitchers expanded and complete games began to decline in number.
In 1903, when National League President Harvey Pulliam hired John Heydler to be the league secretary, the young Heydler made it one of his goals to standardize scoring practices, and in particular for the attribution of wins. He issued guidelines to official scorers that required a starter to pitch "the majority" of a ballgame to be eligible for a win. There were a number of exceptions to this however, for example if a pitcher left a game early with his team enjoying a big lead, or if he left because of an injury (which led to pitchers making sure to tell reporters that they had been removed from the game after giving up a pair of hits with a a one-run lead in the 5th because they had an upset stomach or had felt a twinge in their elbow, and for no other reason), and so on. The league president would often overturn the decision of the game's official scorer. The latter was a particular problem in the American League, where President Ban Johnson would make such decisions on what appears in retrospect to be whims and personal bias, rather than any set criteria. Game 2 of the 1929 World Series, in which George Earnshaw was credited with a win while pitching only four innings, is an example of the practice of the time (in this case, the prevailing American League scoring practice of the time was followed).
As the use of relief pitchers continued to expand, confusion only grew, as scorers began to interpret the "majority of the game" provision more liberally, crediting the starter with the win when he had pitched more than any reliever even if that amounted to only three innings or so. Finally the modern rule was adopted before the start of the 1950 season, and while there are a couple of games every year in which the identity of the winning pitcher is left to the discretion of the official scorer, the five-inning rule for starters is now the universal norm and there are no more aberrant wins attributed.
The only exception to the five-inning rule comes in the case of a rain-shortened game which lasts less than seven innings. In such cases, a starter only has to pitch four innings to be eligible for the win, something which happens very infrequently (there were no such wins awarded between 1949 and 1978). Ironically three of the last four major league pitchers to have been awarded a win under those unusual circumstances won the last game of their career thus: Larry Luebbers in 1999, Chris Michalak in 2006 and Andrew Carpenter in 2009 - the fourth is CC Sabathia who gained such a win as a rookie in 2001.