Florreich entered the AAGPBL in 1943 with the
South Bend Blue Sox, playing for them two and a half years before joining the
Kenosha Comets (1945-'46) and
Rockford Peaches (1947-'50). Although originally a
center fielder with South Bend, she switched to
third base with Kenosha in 1945 and became a part-time pitcher in 1946, joining a pitching staff bolstered by
Helen Nicol. During the 1945 midseason, South Bend sent Florreich, who was batting .223, along with
Dorothy Schroeder (.179) to Kenosha in exchange for
Pauline Pirok, who was leading the league with 20 RBI, and
Phyllis Koehn (2nd, 18 RBI). In her first four seasons, Florreich hit a .205 average. While playing at third base for Kenosha in 1946, she only hit .234, but the team counted on her not for her bat but for her fielding and as a pitching prospect. She went 9–16 with a 2.40 ERA in 1946, and improved to 13–19 and a 1.68 ERA in 1947 after being traded to the Rockford Peaches. She was also one of two hundred players to attend the first AAGPBL spring training outside the
United States, which was held in 1947 in
Cuba at the
Gran Estadio de La Habana. Florreich entered the baseball record books in 1949, by leading all pitchers with a 0.67 ERA to set an AAGPBL all-time, single-season mark. She surpassed Rockford teammate
Helen Nicol, who posted a 0.98 ERA, and
Jean Faut of South Bend who ended with 1.10. For the second consecutive year Florreich won 20 games, going 22–7 with nine
shutouts. She also led the circuit with 210 strikeouts, 26
complete games, 269
innings and a .759
winning percentage. In addition, she finished second in wins and shutouts behind Faut, who collected 24 and 12, respectively. Florreich garnered her second All-Star selection while the Peaches clinched their second title in a row. In 1950, Florreich turned in another stellar performance during her final year of play. She made her third straight All-Star appearance, again won 20 games (20–8), recorded a 1.18 ERA, and led the league with 171 strikeouts – 53 more than second place Faut. Her ERA was 0.06 behind leader Faut, and finished second in complete games (28) and third in wins. Florreich also set a personal mark with 22 strikeouts in a nine-inning game. She was injured for the Championship Series against the
Fort Wayne Daisies, but the Peaches still won in seven games to become the most successful team in All-American Girls Professional Baseball League history, winning four titles in 12 seasons, including three in a row. ==Career statistics==