Alexander (hamstring) will start at shortstop and bat second in Wednesday's game against the Cardinals.
Alexander didn't play in either of Arizona's last two contests after leaving Sunday's 5-3 win over the Giants with right hamstring cramping, but he'll be back in action for the series finale in St. Louis. Diamondbacks manager Torey Lovullo will tinker with his lineup and move Alexander up to the two hole after the rookie had batted no higher than sixth in any of his previous 13 starts.