In baseball, a closing pitcher, more frequently referred to as a closer (abbreviated CL), is a relief pitcher who specializes in getting the final outs in a close game when their team is leading. The role is often assigned to a team's best reliever. Before the 1990s, pitchers in similar roles were referred to as a fireman, short reliever, and stopper. A small number of closers have won the Cy Young Award. Dennis Eckersley, Rollie Fingers, Goose Gossage, Bruce Sutter and Hoyt Wilhelm are closers who have been elected to the Baseball Hall of Fame.

A closer is generally a team's best reliever and designated to pitch the last few outs of games when their team is leading by a margin of three runs or fewer. Rarely does a closer enter with their team losing or in a tie game. A closer's effectiveness has traditionally been measured by the save, an official Major League Baseball (MLB) statistic since 1969. Over time, closers have become one-inning specialists typically brought in at the beginning of the ninth inning in save situations. The pressure of the last three outs of the game is often cited for the importance attributed to the ninth inning.

Closer may refer to:

Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond. Players on the batting team take turns hitting against the pitcher of the fielding team, which tries to stop them from scoring runs by getting hitters out in any of several ways. A player on the batting team can stop at any of the bases and later advance via a teammate's hit or other means. The teams switch between batting and fielding whenever the fielding team records three outs. One turn at bat for each team constitutes an inning and nine innings make up a professional game. The team with the most runs at the end of the game wins.

Evolving from older bat-and-ball games, an early form of baseball was being played in England by the mid-eighteenth century. This game was brought by immigrants to North America, where the modern version developed. By the late nineteenth century, baseball was widely recognized as the national sport of the United States. Baseball is now popular in North America, parts of Central and South America and the Caribbean, and parts of East Asia.

Mariano Rivera (born November 29, 1969) is a Panamanian right-handed baseball pitcher who has played 18 seasons in Major League Baseball (MLB) for the New York Yankees. Nicknamed "Mo", Rivera has served as a relief pitcher for most of his career, and since 1997, he has been the Yankees' closer. A 12-time All-Star and five-time World Series champion, he is MLB's all-time leader in saves (608) and games finished (892). His accolades include five American League (AL) Rolaids Relief Man Awards, the 1999 World Series Most Valuable Player (MVP) Award, and the 2003 AL Championship Series MVP Award.

Rivera was signed by the Yankees organization in 1990 as an amateur free agent in Panama, and he debuted in the major leagues in 1995. Initially a starting pitcher, he struggled in the role and was consequently converted to a relief pitcher. After a breakthrough season in 1996 as a setup man, he became the Yankees' closer in 1997. In the following years, he established himself as one of baseball's top relievers, leading the major leagues in saves in 1999, 2001, and 2004. Rivera's presence in the late innings of games to record the final outs has contributed to the Yankees' success in the late-1990s and 2000s, particularly in the postseason where he has set numerous records, including lowest earned run average (ERA) (0.70) and most saves (42). His pitching repertoire consists primarily of one pitch, a sharp-breaking, mid-90s mile per hour (mph) cut fastball that has been called an all-time great pitch.

Trevor William Hoffman (born October 13, 1967) is an American former baseball relief pitcher who played 18 years in Major League Baseball (MLB) from 1993 to 2010. A long-time closer, Hoffman pitched for the Florida Marlins, San Diego Padres, and the Milwaukee Brewers, including more than 15 years for the Padres. He was the major leagues' first player to reach the 500- and 600-save milestones, and was the all-time saves leader from 2006 until 2011.

Hoffman played shortstop collegiately at the University of Arizona and was drafted in the 11th round by the Cincinnati Reds. After not having much success batting, Hoffman was converted to a pitcher, throwing up to 95 miles per hour (mph). The Marlins acquired him in the 1992 expansion draft, and he pitched in Florida until he was traded to the Padres mid-season in 1993 in a deal that sent star Gary Sheffield to the Marlins. Hoffman recorded 20 saves in 1994 in his first season as Padres closer, and in the following years, he became the face of the franchise after Tony Gwynn retired. He collected at least 30 saves each year for the next 14 years, except for 2003 when he missed most of the year recovering from shoulder surgery. After San Diego did not re-sign him, Hoffman pitched two years with the Brewers before retiring in 2010.