William Francis Plummer (born March 21, 1947) is an American former professional baseball player. He played in Major League Baseball as a catcher for the Chicago Cubs, Cincinnati Reds and Seattle Mariners.
Born in Oakland, California, Plummer attended Anderson Union High School in Anderson, California. He was signed by the St. Louis Cardinals on April 25, 1965 as an amateur free agent. He played three years in the Cardinals' minor league system, then was drafted by the Cubs on November 28, 1967 in the Rule 5 Draft.
Plummer spent nearly all of 1968 in the minors, making his major league debut at age 21 on April 19, 1968 with the Cubs in a 9-2 road loss to the Cardinals. Pinch-hitting for Chuck Hartenstein, he struck out against Hal Gilson. He had only one more at-bat that season and played in just two games.
He played in the minors for all of the 1969 season. He was traded to the Reds on January 9, 1969 and again played most of the season in the minors, although he was called up to the Reds long enough to play in four games with nine plate appearances, including his first career hit.
While never a regular starter—he was Johnny Bench's backup catcher during the Big Red Machine years—he did play solid defense with a .983 fielding percentage. He was a lifetime .188 hitter. His most memorable game was in 1974 when he hit two home runs off Baseball Hall of Fame member Steve Carlton.
Plummer's career as a backup catcher was profiled in a Sports Illustrated feature story on July 18, 1977 entitled, "Few Things Come To Him Who Waits: The Reds' Bill Plummer plays behind the finest catcher in baseball -- at times." "I've always wondered how Bill would do if he played two months straight," said Pete Rose. "He's a physical fitness nut, and if hard work means anything, he would do all right." The article's writer said of Plummer, "He is a private person. He hoards his time and spends it with his wife Robin and two daughters, Gina and Tricia. He doesn't drink, works out, jogs and plays tennis, and during the winter he labors on his father-in-law's northern California cattle ranch.
After he retired, Plummer stayed in the Mariners system. He managed the Wausau Timbers in 1981. He was the Mariners' third base coach, and when Jim Lefebvre was fired after the 1991 season, he was hired as manager. The Mariners finished in last place in his only season in Seattle, going 64-98.
Plummer has managed in both independent and minor league baseball, having managed the Western Baseball League's Chico Heat from 1997–1999. In 2000, he joined the Arizona Diamondbacks' minor-league system, eventually working his way up to their Triple-A affiliate, the Tucson Sidewinders, which he managed in 2007-2008. Plummer served as the minor league catching coordinator for the Diamondbacks from 2009 to 2012. He managed the Naranjeros de Hermosillo of the Mexican Pacific League for parts of the 2010 and 2011 seasons, taking them to the playoffs in 2010. Also he managed Leones del Caracas in two seasons of Venezuelan Winter League in 1986-87 and 1989-90.
In 2013, he served as manager of the Diamondbacks' Single-A affiliate Visalia Rawhide of the California League in his 22nd season as a minor league coach or manager. Through the 2013 season, he has a career minor-league managing record of 1,328-1,219 for a .522 winning percentage. Since 2014 Plummer had reassumed the role of Arizona Diamondbacks catching coordinator.
Plummer's father, William Lawrence Plummer, pitched in the Pacific Coach League 1921-1927, and his uncle, Earl "Red" Baldwin, was a catcher in the Pacific Coast League catcher from 1915 to 1931. Plummer and Baldwin were teammates in 1924 and 1925 with the Seattle Indians.