A fielder is a player in baseball, softball, or cricket whose job is to catch, stop, or throw the ball when the other team hits it. When a batter smacks the ball into play, the fielders spring into action: an outfielder might sprint to catch a fly ball before it hits the ground, or an infielder might scoop up a grounder and fire it to first base to get the runner out.

Good fielders need quick reflexes, strong throwing arms, and the ability to predict where the ball will go. They position themselves strategically around the field, ready to react the instant the bat makes contact. In baseball, there are nine fielders on the field at once, each with a specific area to cover. The center fielder patrols the deepest part of the outfield, while the shortstop handles the space between second and third base.

The word can also describe someone's skill level: a player known as a “strong fielder” makes difficult catches look easy and rarely makes errors. Fielding well requires constant practice and attention, since even a small mistake, like dropping an easy catch, can change the outcome of an entire game.