Potential is both a glorious and dangerous word. As Hall of Fame coach Bill Parcells famously said, "Potential means you haven't done anything yet."
The intersection of potential and production is a sliding scale based on the individual. Some prospects display outstanding upside yet never produce to expected levels. Others aren't considered elite athletes yet performed at a high level year after year. The label of being a boom-or-bust prospect often exists on the extreme ends of this spectrum.
NFL scouting circles must discern how those things translate to the next level. Evaluators concentrate on traits and an individual's makeup to see if a player's potential is ready to explode at the next level or his skill set falls somewhat short.