I don't think he's on the decline.
But it's pretty obvious his mobility isn't what it was last year. I noticed it a few games ago .... didn't say anything, then my wife even noticed it on Sunday and asked me about it. He looks a little stiff and he's having trouble changing directions.
Like I said, I don't think he's on the decline, but I think he may be nursing some injury that we don't know about. Sorta like Ware's injury earlier in the year ... we could see something wasn't right, then found out about it later.