We can look at his height, weight, reach, speed and all the rest and draw a conclusion about what he "should" be based on other players with the same measurables.

Or..........

We can look at how he plays. And right now he is an above average WR. Could he be elite? I haven't seen anything that would lead me to believe that. So I don't think he's underachieving, I think what we have seen and that is decent play with lousy or backup QB's.

I think you are looking at his measurables and thinking he is underachieving because of them.