Alvarez is starting at catcher and batting ninth Tuesday against the Padres.
Mark Canha is at designated hitter and Tomas Nido is on the bench. Alvarez drew his first major-league start of the season Sunday versus the Marlins and went 1-for-4 with an RBI single. The 21-year-old top prospect had slugged two home runs in four games at Triple-A Syracuse prior to his promotion Friday.