People need to stop over reacting, up until this three game stretch he was the best in the league. Conversely people also need to recognise that their grades do reflect what has happened in the last three games. Look at the plays aside from the 3-4 highlights he performs per game and look at the whole body of work.
Perhaps he is just trying too hard to make the big play on every play. Ether way he has already shown he deserves to be at the top of the middle linebacker rankings and will get back to that level sooner rather than later.
The reason for his rent poor grades has been his run defence more than his pass coverage.
He is still a fantastic player but recently teams have been able to get blockers on him and he has shot the wrong gaps. He has made big plays, but a lot of mistakes. But that's just life, he has already proven he belongs in the top tier and he will be back there once he adapts to how other teams are playing him.
Smithy is amongst the top receivers for the amount of forced missed tackles. He is in the top 15 in the league in catch to drop ratio. He only has been targeted 9 times this season with throws over 20 yards, which is less than ginn. Perhaps you are over reacting and it's just that his opportunities have decreased as we have some viable receivers on the team now...