If flying AA (which is likely for someone MIA-based), 24-hour Pre✓ is available at Checkpoint 2, across from Door 3. It is the only checkpoint serving Concourses D & E with a dedicated TSA Pre✓ lane, as the others have been removed from the other checkpoints to make more space for the regular lines.
Not sure about the rest of the airport (Concourses F-J), though. D & E and H & J are connected behind security but F and G are standalone.