"It's a lot more about the "who" than the "how" when it comes to the Buffalo Bills' switch to a 4-3 defense this season. Who they can add to the defense will be far more important in determining their success than how they line up.

One key addition to the defense already is in house. The Bills hope Shawne Merriman can recover from an Achilles tendon injury that has ruined three of his last four seasons. Merriman can put his hand on the ground and rush off the edge as part of a four-man line in passing situations. He has the size and stoutness to hold the edge against the run as a strong-side linebacker.

The Bills need a good complement -- or two -- for Merriman, since his ability to stay healthy for a full season is a question mark.

The 4-3 defense gives the Bills flexibility in looking for solutions. An undersized, 245-pound defensive end can serve as a situational pass rusher. Whether it's an undersized, 245-pound defensive end, a 260-pounder who spent most of his time at linebacker in college or a 285-pounder, it doesn't really matter. The Bills' challenge this offseason is to find a good one (or two) and utilize him in whatever way works best -- standing up or with his hand on the ground; on the line or at linebacker.

"It's tougher to find people for the true 3-4 in a lot of ways," Bills coach Chan Gailey said. "So it makes it a little bit easier to find some people from time to time to run a four-man front than it does a three-man front. It just gets extremely hard to find those outside 'backers year in and year out. It gets tougher and tougher.""