I was ready to blame the issues about 90% on the coaching staff early on, then Zappe played well. When the 4th round, undersized career back-up at best? rookie played well under the same coaching staff, well then I also had to take a closer look at Mac.. and I don't accept the coaching change as a strong enough reason to excuse the extremely poor performance he has put out on the field.
I still think he can regain some of the promise he showed last year, but he needs to start doing it. The OL has been suspect (but also looked vastly superior with Zappe in?). The coaching has been questionable (but surprisingly no one was questioning it during a certain 3 week stretch). Ultimately, Mac needs to do a much a better job controlling the things he can control. If what he is currently showing is his ceiling with this staff and this OL, it's not good enough and we should try the other guy (if there's not significant improvement by, say, after the bye).