Stephan Mathias Mesner
- Bats Right, Throws Right
- Height 5' 9", Weight 178 lb.
- Debut September 23, 1938
- Final Game September 30, 1945
- Born January 13, 1918 in Los Angeles, CA USA
- Died April 6, 1981 in San Diego, CA USA
Infielder Steve Mesner signed his first pro contract as a 16 year old high school student. He earned the nickname "Boy Wonder" when he hit .331 for the Los Angeles Angels of the Pacific Coast League as a 17 year old the follwoing season.
Mesner broke into the majors with the pennant-winning 1938 Chicago Cubs and got a cup of coffee again with them the next year. He was traded to the St. Louis Cardinals after the 1939 season and spent 1940 with the San Diego Padres of the PCL. After another taste of the majors with the 1941 Cardinals, he was taken by the Cincinnati Reds in the 1942 Rule V Draft. He was the Reds regular third baseman during the World War II years from 1943 to 1945. Both Mesner's range and fielding percentage were above average. As a hitter he had little power but was among the league leaders in sacrifice hits in 1943 and 1945.
After his big league days, Mesner appeared on a 1946 baseball card for the Sacramento Solons. He played with the Padres again in 1948 and 1949. In 1954, he led the Pioneer League with a .343 batting average.