Who is Buffalo's other defensive end?

The Buffalo Bills made one of the biggest splashes in free agency by signing two-time Pro Bowl defensive end Mario Williams to a six-year, $100 million contract. Buffalo's defensive line is now one of the best in the NFL with Williams and defensive tackles Marcell Dareus and Kyle Williams.

But who will fill the open spot opposite Mario Williams in Buffalo's new 4-3 defense? Here are the candidates:

1. Chris Kelsay

Analysis: Kelsay is a nine-year veteran who might be able to step in -- at least for the short term. He's 32 and had some injuries last season, missing four games. Can Kelsay hold up for 16 games at a more physically-demanding position? Last season he was an outside linebacker in Buffalo's 3-4 defense. Despite injuries, Kelsay still managed to have a decent season with 41 tackles and five sacks. The defense overall seems to play better when he's in the lineup. Kelsay also is one of the leaders in the locker room.

2. Draft pick

Analysis: Buffalo is fortunate that the draft this year is stocked with talented defensive ends. Quinton Coples of North Carolina, Melvin Ingram of South Carolina, Whitney Mercilus of Illinois, Andre Branch of Clemson ... the list goes on. The Bills hold the No. 10 overall pick, and drafting a defensive end in the first round is certainly an option. I think a good plan would be to start Kelsay, and within the first two rounds, draft a defensive end that can be molded into a starter.

3. Shawne Merriman

Analysis: Merriman is another candidate, but he certainly has question marks. For starters, he had another season-ending Achilles injury. He expects to play next season, but he is not the explosive player he was when he first entered the NFL with the San Diego Chargers. Secondly, Merriman played most of his career as an outside linebacker in a 3-4 defense. Most believe it's easier to make the transition back to a 4-3 defensive end, but it would be a transition for Merriman nonetheless.