Few players have a tougher adjustment to make in transitioning from college to the NFL than those in coverage. Look at a talented rookie who has struggled, such as Dee Milliner with the New York Jets. There are advanced technical aspects to coverage in the NFL that must be learned, scheme-specific skills that must be honed, and then there's just the reality that every week you're facing a wide receiver who is as good as any receiver you might have faced in college. You just can't ever let your guard down.
7hAdam Schefter and Chris Mortensen