Carson Palmer is John Elway minus the wheels. Palmer has the best arm I have seen since Elway played. I don't see the Bengals rushing out to get a QB to replace Jon Kitna as his backup...so I wouldn't be overly concerned here. I expect Palmer to start the 2006 season and this makes him (at worst) a 4th round pick in redrafts.
So you ignore injury risk completely?
As of right now I would say you have to. Now if you are involved in a redraft next month and Palmer has a setback, and this leads to the Bengals getting a Joey Harrington or another QB with NFL starting experience, then you obviously must reconsider. But for right now, follow suit with what Cincy is doing here and ignore the risk. The Bengals are currently a playoff team with Super Bowl aspirations. They would be foolish as an organization to pass (NPI) on getting a QB if they had any doubts about Palmers ability to start the season healthy...