William Francis Plummer was an American professional baseball player and manager. He played in Major League Baseball as a catcher in 1968 and then from 1970 to 1978, most notably as a member of the Cincinnati Reds dynasty that won four National League pennants and two World Series championships between 1970 and 1976. He also played for the Chicago Cubs and the Seattle Mariners.

The Big Red Machine is a nickname for the Cincinnati Reds baseball team that dominated the National League from 1970 to 1979 and is widely recognized as being among the best in baseball history. The team won six National League West Division titles, four National League pennants, and two World Series titles. Between 1970 and 1979 the team averaged over 95 wins a season, with a total record of 953 wins and 657 losses.