Put simply, Kyle Williams has been one of the Buffalo Bills' best players for a decade now - despite the fact that he has routinely been overshadowed, to varying degrees, by higher-profile and more productive teammates.
People tend to forget that Williams walked into Buffalo's starting lineup as a fifth-round drafted rookie out of LSU in 2006, ahead of draft classmate John McCargo, a first-round pick. He has been there ever since, with rare exceptions to account for injuries; he has started 125 games thus far in his Bills career.
Earlier in his career, before Williams entered his prime and was merely a solid, support-level starter on some bad defenses, it was easy to overlook Williams. For the first four years of his career, he deferred to veteran defensive end Aaron Schobel on the defensive line, while bigger-name teammates such as London Fletcher, Paul Posluszny, and Jairus Byrd, to name just a few, stole headlines.
It wasn't until the year after Schobel retired, in 2010, when Williams emerged as one of the Bills' best players at any position - and he did so at a time when fans and media members alike questioned his long-term fit for Buffalo defensively. That year, he earned his first Pro Bowl nod with a 5.5-sack campaign as, essentially, the lone consistently disruptive presence on an awful defensive unit. That was the peak of Williams' notoriety; he missed most of the 2011 season with a foot injury, and the team signed Mario Williams to (what was at the time) the richest contract given to a defender in NFL history prior to the 2012 season.
Yet despite the shadow that Mario Williams and 2011 No. 3 overall pick Marcell Dareus have cast on Kyle Williams since - on a bad 2012 defense, a solid 2013 defense, and an emerging defensive power in 2014 - the veteran has continued to hum along, picking up two more Pro Bowl nods in the past two seasons and establishing himself as one of the better, more underrated defensive tackles in all of pro football. He has ranked in the Top 10 in Pro Football Focus metrics amongst pass-rushing defensive linemen since 2010 (discounting 2011, when he was injured), and in the Top 15 among all defensive linemen in that same stretch, as well, peaking at No. 2 overall in 2010.
He is not the Bills' best defensive lineman, let alone the team's best player, but he is a consistent week-to-week presence, a team captain, and clearly one of the most important figures on a team trying to end a lengthy playoff drought. That remains true whether you consider him the Bills' worst starting defensive linemen, or their best; both can be argued legitimately (though the necessity of doing so is probably time ill spent). The play of Buffalo's defensive line is of the utmost importance to the team's ultimate level of success in 2015. Williams isn't the star of that group, but he is its leader.