Santana (hip) is out of the lineup for Tuesday's game against the Astros, Alec Lewis of The Athletic reports.
Santana exited Monday's series opener with a Grade 1 right hip flexor strain, so his absence from the lineup a day later comes as little surprise. For now, the Royals are labeling Santana as day-to-day, but he'll likely need to make some noteworthy progress in his recovery by the end of the week in order to avoid a trip to the injured list. Ryan O'Hearn will cover first base in Santana's stead Tuesday.