Stephenson will start at catcher and bat third Sunday against the Cardinals.
He'll crack the lineup for the second time in the series after going 2-for-4 with two runs and an RBI in Friday's 6-5 win. Most of Stephenson's starts in recent weeks have come against left-handed pitching, but he'll take aim at a right-hander (Johan Oviedo) while top backstop Tucker Barnhart sits for the day game after a night game.