Well hell, I'm going all with the upside on this deal.
First, its good for Krenzel, he gets a chance at being #2 or #3.
Second its good for the Bengals, they get a chance at having Krenzel in that #3 or better spot. (as others mentioned, de Brown family may look at this as dollars and sense).
Third, (horn tooting), I suggested back when he was cut by Da Bears that the Bengals might be a logical safe haven for Craig's services.
Overall, I reckon this is Craig's best chance to show what he can do. If the Kitna dump scenario plays out there is a practically certain chance that for at least one week in the season the Bengals will need the services of a tried back-up. The Bengals O-line last year, and this one coming, is better than the mesh-vest he worked behind in Chicago last year. Get Craig's timing to speed up and he could carry a team when needed. Frankly, based on his record in Chicago he could do more.
No way he replaces the franchise golden boy, but a smart young man like Krenzel can make a lot of hay working in the background. Plus, maybe he works the whole thing like John Frank did in SF, keep his hand in on both the medical and sports fronts -- keeping his options not merely open, but fully active. There are some pretty well respected Sports Medicine practioners in the area .. the possibilities are all there should he want to take full advantage of the situation.