Jalen Hurts and Tua Tagovailoa (2017)
It wasn't anything close to a 50/50 split (at least until Tagovailoa relieved Hurts at halftime of the national championship game). However, if you're picking any quarterback duo for the list, this is the obvious choice. Long renowned for great running backs and defenses, this is when Alabama dove headlong into the current era of passing dominance.
Eddie Lacy and T.J. Yeldon (2012)
Alabama has had two future NFL players in its backfield far more often than not in the past decade, but this was the one time when there wasn't a clear divide between the starter and the backup.