There's a reason some people say Devin Hester is overrated. He's crazy fast and agile. But he can't cover (even tho he was D-back in college), and he's not a good pro receiver either (even tho he played that position as well in college). He did not refine the receiving skills needed (catching passes, route running, finding open spaces to sit it for short passes) nor did he refine his coverage skills (using his hands at the line of scrimmage, forcing receivers into a particular area, playing physical without getting flagged, baiting the QB into bad throws).
Most athletes don't play like Deion or Hester or Chris Gamble or Charles Woodson. They're like Troy Smith (high school athlete converted into a QB), they did alot of things in high school and the coach says "it looks like this is what you do best, so we're gonna work on that".