Roland Glen Fingers is an American former right-handed relief pitcher in Major League Baseball who played for three teams between 1968 and 1985. His effectiveness helped to redefine the value of relievers within baseball and to usher in the modern closer role. A seven-time All-Star, he led the major leagues in saves three times, and was named Rolaids Relief Man of the Year four times. He first gained prominence as a member of the Oakland Athletics championship teams of the early 1970s, when his flamboyant handlebar mustache made him perhaps the most identifiable member of The Mustache Gang, which led Oakland to become the only non-New York Yankees team ever to win three consecutive World Series titles. Fingers was named the Most Valuable Player of the 1974 World Series after earning a win in the opener and saves in the last three games to secure the title.

In baseball and softball, a relief pitcher or reliever is a pitcher who pitches in the game after the starting pitcher has been removed because of fatigue, ineffectiveness, injury, or ejection, or for other strategic reasons, such as inclement weather delays or pinch hitter substitutions. Relief pitchers are further divided informally into various roles, such as closers, setup men, middle relief pitchers, left/right-handed specialists, and long relievers. Whereas starting pitchers usually throw so many pitches in a single game that they must rest several days before pitching in another, relief pitchers are expected to be more flexible and typically pitch in more games with a shorter time period between pitching appearances but with fewer innings pitched per appearance. A team's staff of relievers is normally referred to metonymically as a team's bullpen, which refers to the area where the relievers sit during games, and where they warm-up prior to entering the game.