I think that the coaches hammered into him that he could not take chances with his body; that he needed to stay healthy and on the field from now on. Sage advice, yes, but I think it bled over into his throwing game. He went from trying not to get hurt to being afraid to make mistakes. He needs to know the difference.
The high fade was simply inexperience. That pass had no chance in yesterday's wind. Look what happened later on when Roethlisberger threw a corner route into the end zone: instead of lofting it, he threw it fairly flat and it cut through the wind right into his receiver's hands. EJ needs to realize this isn't Tallahassee; this is the Northeast.