Ken O’Dea was traded on December 11, 1941 along with Bill Lohrman and Johnny McCarthy to the St. Louis Cardinals for Johnny Mize. The Cardinals also had an All-Star catcher in Walker Cooper, so O’Dea once again found himself in a back up role.
When Cooper was inducted into the United States Navy in 1945, O’Dea was finally given the opportunity to be a starting catcher. He made the most of the opportunity, posting career-highs in hits (78), runs (36), runs batted in (43), extra-base hits (24), and games played (100). O’Dea’s pitch calling skills helped the Cardinals pitching staff lead the league in shutouts as the team finished the season in second place, three games behind the Chicago Cubs. He also led National League catchers in fielding percentage and in base runners caught stealing, and finished second to Phil Masi in assists. He might have been an All-Star for the first time, but the 1945 game was cancelled on April 24 due to strict war-time travel restrictions and no All-Stars were named that season. In place of the All-Star Game, seven interleague games were played. The Associated Press sportswriters named O’Dea as an All-Star, a reserve catcher for the National League team.