Duvall, who leads the Braves with 5 RBIs in the series, will bat sixth and start in left field Wednesday against Cardinals ace Jack Flaherty.
Left-handed hitting Matt Joyce, who started each of the first four games, will be available off the bench.
Despite not starting yet in this series, Duvall has delivered some critical hits for the Braves. His two-run pinch-hit home run off Flaherty in Game 2 provided Atlanta with some much-needed insurance in a 3-0 victory.
Duvall also had a clutch hit in Game 3, when he hit a two-run go-ahead single in the ninth inning to lift the Braves to a 3-1 victory.