He is sick, no doubt.
I even think comparing him to Harvin and Hester is not totally out of line.
However:
Devin Hester is 5'11, 190
Percy Harvin is 5'11, 184
Tavon Austin is 5'8, 174
I will make this argument for Austin though; he is more sturdy,imo, than his size on paper shows.
I recall when Chris Johnson came out and so many questioned his durabilty. I thought he was much stronger than some thought for his size.
Well, 5 straight 1000+ yard seasons, ave 1377 yards per season, nearly 300 carries per year and still nearly 4.7 ypc.....and not one game missed due to injury.