It was more a matter of management and the coaching staff wanting an improvement (or so they thought) at the position.
When Harris was given time and a clean pocket he could throw with anyone in the game. He wasn't nearly as good when things broke down.
I thought at the time they should have been a little more patient with him. Thought the same thing with Jaworski, who turned around and had a solid career with Philly, even leading them to a Super Bowl.