Offline
Neither Kamara nor Ingram needs to be "ready" to be a lead back because Payton hasn't employed a "lead back" system in his 12 seasons as coach. It's been by committee just about the entire time. And more often than not, it's worked.
I think your premise is off. Payton usually has 3 or 4 backs on the roster. With Kamara being as good as he is and Ingram being Ingram, it's given Payton the freedom to only carry 3 if he wants to. But even when we had Deuce or Reggie or Ingram, there was always Sproles, PT, Ivory, Peterson, Cadet and the rest.