Five years ago, the notion of trading Brett Favre was rarely taken as serious possibility by a vast majority of Packers fans, and maybe NFL fans for that matter. 2008, Brett was traded from the Packers to the Jets, even though Brett said he'd retire before playing for another team. That's neither here nor there.
There is some chatter if the Colts acquiring (earning) the 1st over all draft selection and using it on Stanford QB Andrew Luck. If they do, some feel the Colts should TRADE Peyton Manning. I initially thought this would be a good idea, then after thinking about it, not so much.
It would be better for Andrew Luck to sit behind Peyton Manning for a year or two, regardless of how well Peyton Manning plays to learn his work ethic and leadership and nuances of the NFL. There is no one better to learn from than Peyton Manning in my opinion. Sure, Andrew Luck could be a 3500 yard, 35 td 15 int QB out of the gate, but there is no question that learning from Peyton would raise his ceiling of potential.
Also, you are not going to get much in trade for Peyton Manning as he's closing in on 40 years old (currently I believe he is 36). Minnesota drafted a QB in the first round this past draft therefore the team that enjoys old over the hill QBs is likely out of said business.
Colts get 1st overall, use it on Andrew Luck, let him learn from Peyton for a year or two and prepare for life after Peyton Manning because he is not going to last forever, but the team is going to need to think ... future.