Horwitz is starting at designated hitter and batting eighth in Tuesday's contest in Miami.
Horwitz didn't start the first game after his promotion on Friday, but he's subsequently been in the lineup for each of the last three contests. It appears that he could carve out a regular DH role against right-handers while Brandon Belt (hamstring) is sidelined. Horwitz has reached base four times and driven in one run in his first eight major-league plate appearances.