Win–loss record (pitching)

The official scorer does not assign a winning or losing pitcher in some games which are forfeited, such as those that are tied at the time of forfeiture.

The first is that a starting pitcher must complete a minimum of five innings, the length of an official game, to earn a win.

Failure to do so results in the ineligibility to be the winning pitcher, even if he last pitched prior to the half-inning when he maintains his team's lead.

The second exception applies if the relief pitcher who last pitched prior to the half-inning when the winning team took the lead the last time was "ineffective in a brief appearance" in the official scorer's judgment, in which case the win is awarded to the succeeding relief pitcher who, in the official scorer's judgment, was the most effective.

For example, Shohei Ohtani, the starter for the American League, was awarded the win in the 2021 All-Star Game despite throwing only 14 pitches in a single inning.

If a pitcher leaves the game with his team in the lead or with the score tied, but with the go-ahead run on base, and this runner subsequently scores the go-ahead run, the pitcher who allowed this runner to reach base is responsible for the loss.

If the relief pitching successfully completes the half-inning without surrendering the go-ahead run, the departed pitcher cannot receive a loss.

For example, on April 13, 2007, Carlos Zambrano of the Chicago Cubs was facing the Cincinnati Reds in the top of the 5th inning.

The pitcher who replaced him, Will Ohman, proceeded to allow two of the runners on base to score, giving the Reds a 6–5 lead.

A pitcher who starts a game but leaves without earning either a win or a loss (that is, before either team gains or surrenders the ultimate lead) is said to have received a no decision, regardless of his individual performance.

The New York Times wrote in 2011 that as advanced statistics have expanded, a pitcher's win–loss record has decreased in importance.