I'm of the opinion that you really can teach accuracy. Having coached baseball and softball for most of my adult life, I rarely see a college athlete who is able to make drastic improvements (some yes, but huge improvements = no). It is kind of a sixth sense thing, and as much as like EJ, I just don't see him getting that much better.
Yes, there are mechanical issues that can be fixed, and they will help; but really, after fours years at top Division 1 school, two in the NFL, do we really think he has major mechanical flaws that have not been addressed? Maybe a tweak here or there, but as any experienced coach will tell you, with elite athletes, most of those are just mental things trying to help them build confidence. Which leads to this observation . . .
The one exception I will say to what I write above, is if the accuracy problem comes from lack of confidence or hesitation—then it is a mental issue—which, with success can be over come.
For him, I do hope that he can work through this.