Baez (back) isn't starting the second game of Wednesday's doubleheader against the Nationals, Anthony DiComo of MLB.com reports.
Baez wasn't in Tuesday's lineup due to tightness in his lower back, but he appeared as a pinch hitter and went 0-for-1 with a strikeout. He'll likely be available off the bench again in Wednesday's nightcap, but Jonathan Villar will start at shortstop and bat seventh.