This is what espn insider had to say:
Buffalo Bills safety Donte Whitner is set to hit free agency this offseason, and it's currently unclear if the team plans to extend his time in Western New York. As a result, Sal Maiorana of the Democrat and Chronicle examined the team's options at the position, given the availability of some other free agents at the position.
In Maiorana's view, though the team has been speculatively linked to former Indianapolis Colts safety Bob Sanders, signing him would be a mistake. Comparing Sanders to Whitner in major stat categories, he doesn't think that the injury-prone Sanders stacks up too well. In essence, the fact that Whitner was drafted eighth overall has worked against him, but from a pure value standpoint, he may actually be a better choice than Sanders.
As for Oshiomogho Atogwe, Maiorana believes the former St. Louis Rams safety may make the best option of the three, if the salary demands are equal. [Editor's note: Howard Balzer of 101 ESPN reports that the Bills are interested]. Atogwe has stayed reasonably healthy and been a productive ball-hawk during his career thus far.
As noted above, there's a chance that Whitner and the Bills will be able to extend their relationship, but we'll be able to tell how serious they are on that front by whether they host one of the other two prior to the March 4 deadline.