Fieldin Henry Culbreth III is an American former umpire in Major League Baseball (MLB). He worked in the American League from 1993 to 1999 and in both major leagues from 2000 until his retirement in 2021. Culbreth was promoted to crew chief prior to the 2013 season. Culbreth wore number 42 while he was an American League umpire, then changed to 25 in 2000 after the MLB umpires were unified into one crew.

In baseball, the umpire is the person charged with officiating the game, including beginning and ending the game, enforcing the rules of the game and the grounds, making judgment calls on plays, and handling the disciplinary actions. The term is often shortened to the colloquial form ump. They are also sometimes addressed as blue at lower levels due to the common color of the uniform worn by umpires. In professional baseball, the term blue is seldom used by players or managers, who instead call the umpire by name. Although games were often officiated by a sole umpire in the formative years of the sport, since the turn of the 20th century, officiating has been commonly divided among several umpires, who form the umpiring crew. The position is analogous to that of a referee in many other sports.