Carson Palmer is demanding a trade or he'll retire. If you're shocked by that first sentence, then call Geico. It's so easy, even you can do it. Of course, if Palmer finally convinces the team that he will retire if he's not traded (a threat the team still doesn't take seriously), the Bengals will have acquire other quarterbacks and you might as well push the position near the top of the "Team Needs" list. Draft. Free Agency. The Bengals will have several avenues to find a quarterback that could fill in until a more long-term franchise-level quarterback is found.
Even though there will likely be a rookie wage scale, a quarterback drafted fourth overall will cost a ton. And few draftnics are labeling this year's crop of quarterbacks as franchise-level players. However, a quarterback drafted in the second, if not third, round could make sense while the team signs a veteran free agent to ease the transition for the rookie quarterback (ala, Kitna/Palmer).
That being said, the team will need a quarterback either through the draft and likely through free agency. Even with the off-handed chance Palmer returns, the team will still need to develop a backup quarterback. There is always Dan LeFevour, the team's third-string quarterback; though we're not sure if Lewis has ever mentioned LeFevour.
If the Bengals learned anything this offseason, it's that the threat of Palmer leading had to have the team taking night classes in Long Term Planning 101. First week: Plan for a contingencies, develop a backup quarterback that could replace your starter.