St. Louis activated Carpenter (oblique) from the 10-day injured list prior to Saturday's game against the Brewers.
Jose Fermin had been leading off against lefties, but with the Cardinals set to face three right-handed starters in a row, Fermin was sent to Triple-A Memphis, and the lefty-hitting Carpenter was added to the active roster. The 38-year-old designated hitter went 3-for-10 with a run scored in three games before getting injured April 1.