Notable NFC West appearances on the Advanced NFL Stats player pages tracking measurable contributions through Week 13:

• Seattle's Chris Clemons and Arizona's Calais Campbell appear with Minnesota's Jared Allen and the New York Giants' Jason Pierre-Paul among the top four defensive ends. Clemons and Campbell are strong against run and pass. The interception Campbell made against Philadelphia stands out as a highlight. Michael Vick's pass hit Campbell in the upper body from close range. Campbell seemed to absorb the ball.
• Seattle's Doug Baldwin ranks ninth among receivers. Wes Welker, Victor Cruz, Anquan Boldin, Jordy Nelson and Greg Jennings comprise the top five. Baldwin ranks just ahead of Calvin Johnson and Mike Wallace. The rankings consider only how players' contributions affected their teams' probability for winning. Baldwin is tied for the NFL lead in third-down receptions for first downs. He has 18, one more than Welker.
• Arizona's Darnell Dockett and San Francisco's Justin Smith top the list of NFL defensive tackles. Both play defensive end in 3-4 base defenses. They also play tackle. The NFL has listed them as defensive tackles for years. That is the position they would play in a 4-3 defense. Smith has stood out all season; he leads the defensive tackles listed with 14 quarterback hits. Dockett made impact plays against Dallas in Week 13. This is a strong list. Haloti Ngata and Ndamukong Suh are in the top six.
• San Francisco's Delanie Walker outranks Vernon Davis among tight ends. Davis has outproduced Walker, but Walker's contributions have been more pivotal to winning. For example, Walker caught the winning touchdown pass against Detroit. Walker's 29-yard scoring catch against Dallas broke a 14-14 tie late in the third quarter. Davis and Walker both rank among the top 13.
• Seattle's Kam Chancellor tops the list of safeties.
• The New York Jets' Darrelle Revis leads cornerbacks, but the 49ers' Carlos Rogers and the Seahawks' Brandon Browner are next, just ahead of ex-49ers corner Nate Clements. Rogers and Browner have combined for nine interceptions.

More: offensive and defensive players by position. It's easy to sort columns by various statistical criteria. These aren't definitive player rankings. They're one way to differentiate player contributions beyond the raw yardage stats available everywhere.