A faulty starter motor can drain a Suburban's battery, but it's not a direct, constant drain like a short circuit. Instead, the drain happens when you try to start the vehicle. If the starter is malfunctioning (e.g., shorted windings, gear problems), it might draw excessive current for an extended period, or even continuously draw a small amount of current even when not engaged. This repeated high current draw during cranking attempts, or a small continuous draw, will eventually deplete the battery.
A bad starter *itself* doesn't continuously drain the battery like, say, a parasitic draw from a faulty interior light. The drain is a consequence of *using* the bad starter. If you're not trying to start the Suburban, a bad starter isn't actively draining the battery.
