Callow entered the AAGPBL in 1947 with the
Peoria Redwings, playing for them during her
rookie season before joining the
Chicago Colleens expansion team for a small time in 1948. She was traded to the
Rockford Peaches during the midseason and remained with them for the rest of her career, including in three consecutive championship titles (1948-'50) and also in the team's last ever game in 1954. Beginning in 1948, Callow led the league in triples for four straight years and ended up with 60 in her career. She started off slow in the home run category with none during her rookie season, but by the rest of her eight years career she belted 55 to top the all-time list. In 1948, Callow ended with a .251
batting average, but tied for second in home runs (6) and led the league for the first time in triples (15). She repeated as the leader in triples in 1949 (11) and 1950 (11). In 1951 she gained her first selection for the
All-Star Team, after recording career-highs in average (.326),
runs (66),
runs batted in (84),
hits (124),
doubles (16),
stolen bases (40),
total bases (172) and
walks (49); claimed her fourth triple title in a row, had the best
fielding percentage of any outfielder, and tied with
Fort Wayne Daisies'
Betty Foss and teammate
Alice Pollitt in home runs (4). In 1952 Callow was unable to repeat the success of the previous season. Nevertheless, she finished third in home runs (8), fourth in triples (6), fifth in total bases (151), eighth in runs (56), ninth in RBI (49), and still made the All-Star Team. But she rebounded in 1953, hitting .303 (3rd league-best) with eight home runs (2nd) and 58 RBI (7th). She also scored 58 runs (8th) and stole 37 bases (8th), while making the All-Star Team for the third time. By the time of her last season, Callow said goodbye hitting .324 with 20 home runs, 58 RBI and 23 stolen bases in 273 at-bats. In addition, she joined
Joanne Weaver as the only two AAGPBL players to reach the 20 home runs and 20 stolen bases plateaus in the same season. She is also one of five players to collect 400 or more career-RBIs, ranking third (407) behind
Dorothy Schroeder (431) and
Inez Voyce (422).
Elizabeth Mahon and
Pepper Paire recorded exactly 400 RBIs. The league ceased operations shortly after Callow's 27th birthday. Considering she had only 2,765 at-bats in her abbreviated career (Schroeder had 4,129 at-bats), Callow may have been the greatest clutch hitter in AAGPBL history. ==Career statistics==