On Tuesday, after four weeks' worth of waiting around for a foot injury to heal, the Buffalo Bills finally ended the 2011 season of defensive tackle Kyle Williams by placing the sixth-year pro on Injured Reserve. That decision makes permanent a development from the last four weeks brought on by Williams' absence from the lineup: rookie Marcell Dareus is now the Bills' most important - and perhaps even best - defender as the team pushes for the playoffs.

Dareus has had a more active role in George Edwards' defensive fronts in the last three games, all of which Williams missed. In five games playing alongside Williams, Dareus racked up 11 tackles and one sack. In the three games without Williams, Dareus has been much more productive, accumulating 13 tackles, 2.5 sacks and a fumble recovery. While much has been made about Dareus' supposed switch to nose tackle - which he's done well - the real reason for the uptick in production has been his own progress as a player and his being a much more important factor with Williams' play-making abilities absent.

We'll need to wait until next season to see the full effects of a healthy duo of Williams and Dareus anchoring Buffalo's defense. That never materialized this season. But though it hurts to have Williams out of the lineup, the defensive line is in good hands with the massive frosh out of Alabama.