As the Bills' Year in Review series continues along, today we'll visit one of the primary focuses of the organization based on how they've drafted and signed players each of the past two years.

In 2010, the Buffalo Bills were the worst in the league in stopping the run, despite having a Pro Bowl player plopped square in the middle of their defensive line. After using their third overall pick to help solve those issues, they were better at the start of the 2011 season. But injuries and missed assignments slowly brought them back down to the fifth-worst total in the NFL.

Let's put the microscope on the defensive line.

(Editor's Note: Since some of you haven't realized based on some comments, this does not include an outlook on the pass-rushers on the team, it is for the 3-4 defensive line only. Since they are known as outside linebackers, the pass-rushers will be addressed in the 'Linebackers' Year in Review.)

The Year
For clarification's sake, we're limiting this to the base 3-4 defenders along the line. In that group, there were a grand total of seven players that were used at one point or another throughout 2011. Kyle Williams, Marcell Dareus, Dwan Edwards, Alex Carrington, Kellen Heard, Torell Troup and Lionel Dotson all saw some action at certain points. Collectively the unit combined for 11 sacks -- nearly 38-percent of the Bills' sacks -- even though that isn't necessarily their primary objective. Third overall pick Marcell Dareus accounted for half of that number, and led the team with 5.5 sacks. On the downside, the Bills allowed 4.8 yards per carry and 139 yards per game during the 2011 campaign. All things considered, they allowed 30 YPG less from one season to the next. But the yards per carry stayed consistent both seasons, putting the Bills near the bottom of the league against the run on any given play. Injuries plagued the team for much of the season, and one of the biggest occurred when Kyle Williams could not play the final 11 games of the regular season.

The Great
The defensive line had their best performance of the season while playing north of the border. When the Bills "hosted" the Washington Redskins at the Rogers Centre in Toronto, a completely unique Bills defensive effort was seen. The Redskins couldn't do much of anything, ultimately leading to a 23-0 shutout win for Buffalo. Marcell Dareus had his breakout performance going up against rookie center Erik Cook, accounting for 2.5 sacks. Dwan Edwards even had 1.5 sacks on the afternoon. Overall, it was just a dominant effort by the Bills' defensive line. There's no better indication of this than looking at the Redskins' rushing totals for that game. Ryan Torain was the only running back to get a carry for Washington, and he had just 14 yards on 8 rushes. You can't get much better than that on defense.

The Good
When the Bills defeated the Denver Broncos 40-14 at Ralph Wilson Stadium for their final win of the season, the type of numbers that were put up against them on the ground aren't that staggering against a normal NFL offense. As we all know, that wasn't any ordinary offense that showed up to oppose the Bills on Christmas Eve. With Tim Tebow at the helm, the Broncos transformed themselves in to the top rushing unit in the NFL, mostly due to their quarterback's passing limitations. Tebow, Willis McGahee, Jeremiah Johnson and Lance Ball combined for 133 yards on 35 carries. That's a YPC of 3.8 for a normally struggling rush defense against a particularly potent rushing attack. The defensive line displayed solid knowledge of their responsibilities against the read-option offense that had been gaining some steam in weeks leading up to their matchup. Stopping the run helped the Bills' defense helpTebow to the worst performance of his football career.

The Bad
For this, I'll go with a two-game stretch rather than just one in particular. This two-game stretch was a pre-cursor to the downfall of the defensive line for the majority of final 10 games. It started in the 31-24 win over Philadelphia. Mind you, a win is a win is a win (Yes, I know there are three 'win's there). But this just so happened to be the game where we would last see Kyle Williams in 2011. Even with him for parts of the game, running back LeSean McCoy popped off for 7.3 YPC and 80 yards on just 11 carries. Had the Eagles not been playing catch-up for the entire second half, McCoy could have had a career day. The Bills just had no answer for him. This extended in to the following weekend, a 27-24 loss to the New York Giants. In this contest, the Williams-less Bills were trampled over by Ahmad Bradshaw's 100-plus yard, three-touchdown afternoon. The defensive line didn't get a hand on Eli Manning all game.

The Downright Ugly
205 yards. To Reggie Bush. Need I write more? Okay, I will. In a game that was supposed to be the response to Dolphins' safety saying the Bills laid down in their first meeting, the compete just wasn't there again. Certainly an afternoon to forget for Bills' fans.

The Future
With the Bills potentially switching to a 4-3 next season, it seems most the personnel in this portion of the Year in Review make up one of the deepest on the team. Marcell Dareus and Kyle Williams will be starters next season, whether it's at the zero, three or five-technique. From there, then we'll start seeing front-specific groupings I would imagine. Dwan Edwards will be used in three-man fronts, while Alex Carrington, Torell Troup and Kellen Heard will be the primary rotational pieces. Troup will be returning from back surgery next year, so it will be interesting to see his progress in his third season. I don't expect Lionel Dotson to be back, as shocking as that may be to some of you.

Draft Considerations
In terms of defensive tackles in a four-man look, or the entire line in a three-man front, I think the Bills are all set here. They may look to add a late, late round pick at the position or maybe even an undrafted free agent or two. For the most part, however, this position is set for 2012.

Want More? Here is the link to the first 'Bills' Year in Review' piece:
Quarterback

More to come leading up to the NFL Scouting Combine in February.

Twitter: @JoeB_WGR