Clarence James Maddern (September 26, 1921 – August 9, 1986) was an American professional baseball outfielder who appeared in 104 Major League games for the Chicago Cubs in 1946, 1948 and 1949, and the Cleveland Indians in 1951.

His career was interrupted by service from 1943 to 1945 in the United States Army during World War II, when he served in the 76th Infantry Division.

The biggest moment in his career came the night of September 29, 1947, before a sellout crowd in Los Angeles' Wrigley Field.

The Angels and the San Francisco Seals had finished in a dead heat for the PCL pennant and met in a one-game playoff.

The game was a scoreless tie until Maddern broke it up with a grand slam home run in the eighth inning to give the Angels a 5–0 win over the Seals.