Alan Marshall Clark is a former professional baseballumpire who worked in the American League from 1976 to 1999, and throughout both Major Leagues in 2000 and 2001, wearing uniform number 24 when the American League adopted them for its umpires in 1980, then retained the number when the NL and AL staffs were merged in 2000. Clark umpired 3,392 major league games in his 26-year career. He umpired in two World Series, two All-Star Games, five American League Championship Series, and three American League Division Series. Clark worked second base in the 1978 one-game playoff between the New York Yankees and the Boston Red Sox, which the Yankees won 5-4. He was the home plate umpire in Nolan Ryan's 300th career win on July 31, 1990. Clark and fellow 1976 rookie Greg Kosc were the first American League umpires who never used the outside chest protector, which had been used since the league's formation in 1901 and was mandated in the 1920s by future Hall of Fame arbiter Tommy Connolly. In 1975, the year before Clark's hiring, the American League ruled umpires could use the outside protector or the National League standard inside protector, invented in the 1910s by another Hall of Fame umpire, Bill Klem. In 1977, the AL ruled all incoming umpires had to use the inside protector, an edict which affected new hires Steve Palermo and Durwood Merrill. Umpires active prior to 1977 using the outside protector could continue to use it until they retired or switched to the inside protector. In 2001, Clark was fired by Major League Baseball after downgrading his first classairline tickets to economy class, thus either pocketing funds by selling extra tickets or to gain additional airline tickets for unapproved personal travel. In 2004, he was sentenced to four months in jail and four months on house arrest after a memorabilia scheme resulted in a federal mail fraud conviction. He now is a member at Ford's Colony Country Club in Williamsburg, VA, and lives in that development.
