While part of the Chicago Cubs organization, John Thaddeus Ostrowski also played in the Los Angeles Angels' outfield in a total of 143 games in 1943. In 1944, he occupied both outfield and infield. The next two years found him exclusively in Chicago, but he returned to the PCL in 1947 as the Angels' third baseman, where he played for the next three years. After two seasons back in the majors with the White Sox and Nationals in 1949 and 1950, he returned to the Pacific Coast for the last time to play for the Solons at the beginning of the 1952 season, and finished his baseball career as the Oaks' outfielder in the latter part of the season.