Something that I think is rather interesting is that a generation of QBs is getting further into their 30s and some could be slipping a bit, declining from their peak. There's guys like let's say Manning, Brady, and Gannon who are the types that can stay rocking in their late 30s but they are rarer to come by.
Here's my list:
Matt Schaub (33) has no doubt slipped into this state. He's lost whatever he had. McGloin and/or Carr will be playing soon.
Eli Manning (33) definitely showed some slippage last season; I can see it continuing if they can't get a decent run game going
Josh McNown (35) will be benched by week 3/4
Tony Romo (34) sure, he has Dez and T-Will and Murray coming back but that OL is young and inexperienced, he's a toss up. I can see him putting up an efficient year but his TD numbers may be a little down and that team as a whole is bad.
The aging question marks/prospects:
Jay Cutler (31) -- Unbelievable supporting cast but he really knows how to sh*t the bed
Philip Rivers (32) -- I think he keeps doing well. Has a great supporting cast
Big Ben (32)
Matt Ryan (29)
There's going to be a lot of QB hungry teams in a few years methinks.