4. Safety
The Buffalo Bills lost Jordan Poyer and Micah Hyde this offseason and appear to have their replacements with Taylor Rapp and Mike Edwards. However, similar to defensive tackle the players they have shouldn't dissuade them from drafting a safety early if one falls to them.
The reason that safety is as low as it is in these rankings is that there are not many safeties that I believe are worthy of a first-round pick. In fact, there is only one player that should be considered in these early stages of the NFL Draft and that is Cooper DeJean.
The former Iowa Hawkeye is a versatile player who played a lot of cornerback in college but could be better suited as a safety in the NFL. If the Bills were to draft DeJean, they could give him a chance to start at safety but wouldn't have to rush him onto the field with Rapp and Edwards on the roster.