At corner, the Bills had a lot of question marks. Greer was a question mark in that he had started last season behind Webster and Butler and got on the field due to injury. Youboty gave all the signs of being an outright bust. James was just another Webster-like signing -- a journeyman that one doesn't really want to have to have play. Then, one notices Tom Brady, Randy Moss, and Wes Welker and realizes that in order to compete the Bills can't simply paper over a lack of talent with a "Tampa 2" scheme and moving Donte Whitner around.
The emergence of Youboty was not being counted upon on draft day; and, Greer, thankfully, didn't rest on his laurels and go into a huge tailspin this season either.
I know that doesn't explain why the "best CB in the entire draft" was buried on the depth chart and generally not looking like a top draft pick (I'm not really that down on him -- he's coming from Troy State so it's going to take time, which should've been part of the decision process BTW), nor does it mean the Bills are good enough that they can afford to whiff (or even just bunt their way to first) on top of the order draft picks.