Santana has been sidelined since May 25 because of a concussion after taking several foul balls off his catcher's mask against Baltimore. He was in the lineup the next day as the designated hitter but was scratched after getting a headache.
The 28-year-old Santana also has started games at first base and third base. He is hitting .159 with six home runs and 17 RBIs.
Aguilar was sent to the minors for the third time this season. He made his major league debut May 15 and is 3 for 16 in eight games with the Indians.