What does the drafting of Marcell Dareus do for the Bills' defense? The answer in short is: a ton.

Marcell Dareus' versatility will be a welcome addition to Buffalo's defensive line this season. AP Photo/David Duprey

Interior defensive linemen often struggle as rookies. And Dareus might struggle as well. But by watching him at Alabama, he appears as NFL-ready as any lineman I have seen in some time. A lot of times, young defensive tackles can be lazy and take plays off. Dareus' work ethic and hustle are not problems. In fact, they are strengths.

The Bills' run defense was abysmal in 2010. Their pass rush wasn’t as poor, but it wasn’t a whole lot better either. Dareus should help in both departments. One of the great things about this player is his versatility -- and I fully expect Buffalo to take full advantage of those unique qualities. To me, he is a perfect fit as a 4-3 defensive tackle, either as a 1-technique where he holds the point of attack or as a 3-technique where he is asked to penetrate and beat slower blockers with his extreme quickness.

But the Bills use a base 3-4 scheme, which is what Dareus played in college, excelling at end. Although the Bills look to be predominantly an odd front, expect many variable looks. Adding Nick Barnett on the second level will help make that possible, as he is adept in both schemes, but Dareus is a far more important factor in that equation.

If you don’t know it already, Kyle Williams is a great player. He excels at everything asked of him. Of course, Williams is already proven, but I could see Dareus being very similar to Williams in all manners on the field. At least the Bills hope so. These two are the foundation of the defense. They will probably be the interior pass-rushers on throwing downs. They can line up next to each other at defensive tackle in a four-man front. Personally, it is in that alignment that I think these two could best use their immense skills, but the Bills are not overly equipped with edge rushers to flank them.

One could handle the nose and the other could play end in Buffalo's 3-4, allowing the Bills to use a very athletic three-man front by inserting Alex Carrington, Dwan Edwards, Lionel Dotson or Spencer Johnson as the third lineman. Or Williams and Dareus could both play end in the 3-4 with Torell Troup, a much more traditional nose tackle, hunkering down over center.

With all these defensive linemen mentioned, Buffalo looks to now have a strong rotation up front and a lot more alignment options available to it. Without Dareus (and of course Williams), this just wouldn’t be possible.

Although I still think it is short on pass-rushers off the edge (that will be next year’s offseason project), the Bills' defense should be much more difficult to prepare for in 2011.

Scouts Inc. watches games, breaks down film and studies football from all angles for ESPN.com. Follow Matt Williamson on Twitter @WilliamsonNFL.