Del Castillo is out of the lineup for Sunday's game against the Mariners.
The Diamondbacks are giving Ketel Marte a day off from playing second base but keeping his bat in the lineup at designated hitter, so Del Castillo will be the odd man out of the starting nine as a result. Del Castillo had served as Arizona's designated hitter for the past five games, going 4-for-14 with a home run, two walks, three RBI and an additional run during that stretch. The 26-year-old could soon be at risk of losing hold of his strong-side platoon role, however; Pavin Smith (elbow) is in the midst of a rehab assignment and could take over as the Diamondbacks' primary DH if he's activated from the 60-day injured list during the upcoming week.