Is Tom Brady a quarterback in decline?

Brady's stats have gone down this season compared to his past stellar seasons. We all know he's not as fresh as he used to be, but who could imagine the Patriots without Tom Brady?

There are some good stats...
-2nd in the league in Total QBR
-4th in passing yards and touchdown passes
-tied for 1st in interception percentage

And there are some bad ones...
7.6- Yards per attempt, lowest since 2006
63- Completion percentage, lowest since 2006
5.3- Touchdown percentage, lowest since 2009

So there could be a few reasons why Brady's stats are dropping. It could be because he's getting older. It could be just the fact that his glory days might be over. I don't even want to imagine the day when Tom Brady isn't playing anymore.

Tom Brady