Harrell seems like he COULD become a reliable backup - BUT it is hard to see his potential with the 2nd and 3rd team. Many of us got to see him play behind a line that leaves much to be desired, and I have a hard time evaluating him in such circumstances.
He did appear to settle in a bit more when the OL was blocking well. I did see some nice passes at times, but I was also scratching my head on a few as well. I mostly question his decision making, especially under pressure. There were moments when I feel he should have thrown the ball to the sidelines, an incompletion is better than risking a likely sack or turnover. To be fair, it is hard to blame him for his receiver falling - resulting in a turnover.
I think they need to give him a few reps with the 1st team to get a realistic idea of what he can do. Although some feel this would be a bad idea (more chance for injured starters, less time for guys working for a job) - I don't see any other way to evaluate how well he fits in with this team.
I am split on when it comes to this QB. I have seen good, bad, and WTF from him so far. He shows potential, but very inconsistant in doing so. McCoy could be an option if Harrell can't get it done - I think he would do alright in this offense.