In the NFL, sure things are usually in short supply.
We know Kansas City Chiefs quarterback Patrick Mahomes will chew opponents up through the air. When healthy, we know Tennessee Titans running back Derrick Henry will do the same on the ground. And we know Pittsburgh Steelers edge-rusher T.J. Watt will make life miserable for opposing quarterbacks.
But for every thing that is known, there are five that are not. That includes young quarterbacks, running backs trying to get their career back on track, offensive linemen trying to rebound from an injury-plagued campaign and untested cornerbacks who have been thrust into major roles.