To add to this a bit, I think Sheppard gets lumped in with a lot of bad play. Wannstedt has played nickel/dime for much of the season, so the MLB has been Scott. When teams see this, they run the ball. A lot. And get huge gains. Generally when the Bills have been in their base defense, they have been able to stop the run, except when they run towards Moore who has been terrible in containment.
I think another problem has been at Safety. George Wilson has been horrible in run support. Im not sure if its the scheme or him, but he just doesnt come down in the box and help in the run game. Searcy looks like the guy of the future.