Long-time lurker, first-time poster.
First of all, not too many teams have an excellent backup LT, and it's usually game over if a starting LT goes down. Second of all, how many games did you see Kirk Chambers play? He came in for Jason Peters about a 1/3 of the way into the Giants game and surrendered 1 sack and no QB hurries to Umenyiora, who had 13 sacks on the season. Then he started the following weekend and went against Trent Cole, who had 12.5 sacks, and didn't give up a sack or QB hurry. Hardly a lot of playing time, I would say, but enough to say he wasn't a total basket case considering he didn't get undressed by 2 of the better RDE's in the game. Third of all, the Bills drafted Demetrius Bell to develop at LT. Sure it's not "the middle rounds," but the kid looks like a worthwhile developmental prospect and has more raw tools than you'd find in a mid-round LT.