Just to play with the idea a bit - if for some reason this is the real deal (we all know it isn't, but what the hell) and he is calling it quits, I wonder if it will turn out that the factor was what N.O. did to him in that last game.
Every other team in the league saw that and took careful notes. He knows it, too. He also (now) knows that there are players out there who would love nothing more than to pound him into the turf (not because they don't like him - because he's the best ever, and that's the guy you want to be known for taking down). And then he looks at that line - McKinney will get him killed, and he knows it. Hutch is still good, but he's getting slower, quickly. The guy @ center is no Matt Birk. So forth. It's not a bad line by any stretch, but it's not the line it used to be. If he hadn't been the guy taking snaps last year, that line would have looked a lot worse - he got out of a lot of sacks on his own.
There are a lot of things I've given Brett credit for over the years, but intelligence isn't one of them - perhaps, though, he did the math and realized that at some point there'll be a bullet he can't dodge.
Nah... he's coming back.