Wietelmann's playing career lasted for two decades, from 1937 to 1956. He broke in with the Braves in September 1939 when they were still nicknamed the "Bees", a temporary name change for the franchise begun in 1936 and abandoned after the 1940 season. He was the Braves' regular shortstop during the wartime1943–44 seasons, and their regular second baseman during the final wartime season, 1945, when he hit a career-high .271. In September 1946, he was sent to the Pirates in one of the most important trades in Boston Braves history. In the multi-player transaction, Boston acquired third basemanBob Elliott, who would win the 1947National LeagueMost Valuable Player Award and lead Boston to the 1948NL championship.
After one season with Pittsburgh, Wietelmann was sent to the minor leagues. During his nine-season big league career, he collected 409 hits in 580 games played, with 55 doubles, six triples and seven home runs.