I think that everybody is missing out the coordination that has to be between QB and the lineman. The QB calls the protection at the line and then the linemen makes their calls as to who is going to block whom. Once you took out a 10 cog in Mankins and then have rotating guys playing center, you are going to have serious issues. Hopefully he is hanging with them so that they all finally get on the same page.
If you are the left tackle and the protection calls for the guard to look say on, away gap, then you take a big step to the outside on pass protection. Of course, if the guard misses his assignment and looks to his inside gap first and you expect him to be looking at the outside gap, and the DE takes an inside route, you look like an idiot! It is very complicated, and you have to trust and know what the guy beside you is doing and you have to trust that he knows the calls and that he is going to do his job. Once you start guessing or hesitating because you either don't know your assignment, or you are not sure if the guy next to you knows his assignment. Then you have what the Pats O-line has looked like for three weeks.
I think its "Stork" time. Hopefully he can handle all the line calls at center. Move Connelly back to LG, where there is some history/chemistry and you might start to see an improvement.