For a complete look at my rankings, take a look at this article here. It will be edited to link to these breakdowns as I do them.
Peyton Manning used to be the picture of stability. Never got hurt, always had solid receivers and running backs. Coaching staff was the same guys (for the most part) for his whole career.
What a difference an offseason makes. At least he's still incredibly durable.
Manning lost Head Coach Tony Dungy, a pair of other offensive coaches, and finally Marvin Harrison. While that happened, his main back Joseph Addai came up lame again and the offense as a whole started very slow last season as Manning himself came off injury.
But how much to worry?
Reggie Wayne has played well as the official No. 1 target in the offense. Harrison had been the nominal top cat in the pass attack but really Wayne has been the guy carrying a huge load for many years—Anthony Gonzalez.
Both underperformed last year, but are expected to bounce back. A big reason for the bad year was Manning's own slow start recovering from a knee surgery which caused him to miss large portions of Training Camp.
At running back, rookie Donald Brown is expected to step in and at least spell Addai, if not replace him outright if Addai stays banged up. There is a good chance that the run game will be on track and help to set up the dynamic pass attack which feeds the Colts offensive attack.
As for the head coach, early reports are that Manning is just fine with new Head Coach Jim Caldwell and that the former offensive coaches who "retired" will be back in some capacity.
The disruption should be minimal. All the above concerns are something to keep an eye on but it shouldn't be something which causes you to pass on him if you're looking for a quarterback early, especially if Brees and Brady are gone.
Manning should be a top fantasy quarterback this season again, with less of a roller coaster experience than his owners felt in 2008.