When Mario Williams joined the Buffalo Bills, the NFL took notice.  Before playing one game together, NFL.com writer Gregg Rosenthal wrote a piece that posed the question, "Do the Bills have the best defensive line in football?"  The Bills know what they have in Mario Williams, Marcell Dareus and Kyle Williams, but one question remains: Who will be the starting right defensive end? This question is asked with excitement as the Bills have three players vying for the position, and each brings something to the table: Mark Anderson, Shawne Merriman and Chris Kelsay.

Mark Anderson
Mario Williams was the grand prize of free agency on the defensive side of the ball.  After Williams signed, Mark Anderson was thought to be a solid consolation prize for a team looking for a pass-rusher.  When all was said and done, the Bills signed both.
Mark Anderson is coming off of a 10-sack season with the New England Patriots as a situational pass-rusher.  When talking with Bills fans, many believe Anderson will be the player who wins the starting job.  Per the Buffalo News, Mark Anderson is doing his part to earn the job as he's made a great impression two days into training camp.
"Explosive - that's the word that comes to mind when I think of him. He's just really quick. He's got a lot of good moves and he uses them quickly. He's dangerous on third downs. He's a play-maker, for sure." —Andy Levitre 7/28/2012 Buffalo News



Shawne Merriman was moved to defensive end once the Bills moved back to a 4-3 defense this offseason. But let's be honest and up-front here, Merriman would have to be dominant in training camp and the preseason to even be considered for the starting role.  At one point, Shawne Merriman was looked at as one of the most promising linebackers in the NFL, but in the last two seasons he has only played in eight games due to an achilles injury.  For Merriman to be dominant, he needs to find a way to stay on the field.  Unfortunately for Shawne, he rolled his ankle at Friday's training camp practice:
“He couldn’t go. He rolled an ankle yesterday late. He taped it up and finished, but we held him out today. He went through the walk throughs this morning so it’s not like it’s a hobbling thing. We’re going to make sure he’s ready to go before we bring him back.” —Chan Gailey
It is worth noting that Merriman was dressed for practice at Sunday night's training camp.

Chris Kelsay
Chris Kelsay is Mr. Reliable for the Buffalo Bills.  Going into his tenth season with the Bills, Kelsay has only missed six games.  His numbers are solid, but far from spectacular.  In his career, Kelsay has never finished a season with more than 5.5 sacks.  But where Kelsay is lacking in the pass rush, he more than makes up for in the run game.  Playing against the run isn't the only factor favoring Kelsay.  The experience edge also favors Chris Kelsay.  Out of the three candidates listed as potential starters at the right defensive end position, Kelsay is the only player to be a true starter on the defensive line.
  Games Played and Started at Defensive End
Player Games Played Games Started

 Start Percentage
Mark Anderson 93 21 22.5%
Shawne Merriman 0 0 0
Chris Kelsay 110 88 80%
In an interview with John Murphy, Kelsay had this to say:
“We’ve got a lot of talent on the defensive line, really at every position.  They’re gonna give everybody a look, and it’s gonna be a competition, but it’s fun that way.  It keeps everybody on their toes.  It keeps everybody out here competing, nobody’s missing practice, because you miss practice here or there, you may not be around.”
Final Verdict:
The popular choice may be Mark Anderson, but I feel the Bills would be at their best with Chris Kelsay starting as the right defensive end.  Anderson can be rotated into the game in obvious passing situations, and Merriman, if healthy, can spell both Kelsay and Anderson at different points in the game.