Kenneth Leo Retzer (born April 30, 1934) is an American former professional baseball player.
He was a catcher in Major League Baseball for the Washington Senators from 1961 to 1964, appearing in 237 games played.
Retzer batted left-handed, threw right-handed and was listed as 6 feet (1.8 m) tall and 185 pounds (84 kg).
Born in Wood River, Illinois, Retzer attended Jefferson City Community College and the University of Central Missouri.
He was signed by the Cleveland Indians before the 1954 season, but played his entire major league career for the Senators after Washington acquired him in a September 1961 trade.
He was the Senators' most-used catcher in both 1962 (starting 91 games and platooning with right-handed-batting Bob Schmidt) and 1963 (72 starts in a three-way platoon with Don Leppert and Hobie Landrith).
In 1962, Retzer batted a career-best .285 with 97 hits and eight home runs.
He finished his career with a lifetime batting mark of .264, 182 hits, 14 homers, 72 runs batted in and 65 runs scored.
He caught the first pitch of the 100,000th game played in MLB history' the ball was presented to and preserved in the Baseball Hall of Fame.
He had a lifetime fielding percentage of .983 and threw out 48 of 126 baserunners making stolen base attempts, which is 38.1 percent.
Retzer's 13-season pro career ended in 1967.