By Matt De Lima If you want a backup QB for your roster, these three offer good value. You should always wait on drafting a quarterback. I say that, yet in a recent staff fantasy mock draft, I reached for Buffalo Bills QB Josh Allen with the 2.12 selection. Do as I say, not as I do! I’m of the opinion that in many league formats, you probably don’t need a backup quarterback, let alone a sleeper. For example, in a 10-team league with one starting quarterback, there should be plenty of capable replacements on the waiver wire—so there’s no need. You should use that extra bench spot on another run…