Merrill (ankle) is not in the Padres' starting lineup against the Giants on Monday.
Merrill was forced to leave Sunday's game against the Dodgers after aggravating a left ankle injury that he suffered Friday. He's considered day-to-day for the time being, so he could return to the lineup at some point during the four-game series with San Francisco. Bryce Johnson will start at center field and bat ninth in Merrill's absence.