It was a rocky start for the Chargers' defense, but the team's late-season surge has coincided with improvement on that side of the ball. The undisputed leader is free safety Eric Weddle, who has taken on a multitude of roles this year. In addition to being San Diego's highest-graded defensive player at plus-11.3, Weddle has played all over the field this season after being deployed mostly in a traditional free safety role last year. He has played 44.7 percent of his snaps at free safety, 44.3 percent at strong safety and 10.0 percent covering the slot after aligning at free safety 76.0 percent of the time with limited time in other roles in 2012.
What does this mean for the Chargers' defense? Weddle provides as much range as any safety in the league when playing deep, but he brings linebacker-like skills when playing in the box while also showing the ability to match up with tight ends and slot receivers. His plus-9.5 coverage grade ranks seventh, but San Diego will also blitz him quite a bit; his 50 pass rushes rank fourth. He has gotten home, as well, notching a sack, two hits and eight hurries. Weddle is a rare talent who is comfortable playing deep or in the box, and his performance will be instrumental to San Diego's playoff chances.
With QB Peyton Manning leading the offense, it's hard to find anyone more indispensable than him, but the key to the Broncos' depleted defense is the stability provided by CB Chris Harris. While he generally lines up over the slot, Harris has taken on a much bigger role on the outside since Week 8 on his way to leading the Broncos with 1,059 defensive snaps. His plus-10.9 overall grade ranks ninth among cornerbacks, and he shows well both in coverage (plus-7.3) and against the run (plus-1.9). When lined up over the slot, he has surrendered only 1.10 yards/cover snap, and opposing quarterbacks have a QB rating of only 65.6 when throwing into his slot coverage.
Denver's defense took a major blow when it lost All-Pro linebacker Von Miller to a season-ending knee injury, but Harris may be the next-most-important player on that side of the ball. With players like Hilton, Julian Edelman, Danny Amendola and Eddie Royal manning the slot for the AFC's remaining teams, Harris will be challenged to maintain his status as one of the league's best slot cornerbacks.
A loaded 49ers defense should have the depth to handle any attrition it may encounter, but the offense has had its ups and downs throughout the season and WR Anquan Boldin is one of the keys to making it tick. It could easily be argued that WR Michael Crabtree is the 49ers' best wide receiver as he's quarterback Colin Kaepernick's favorite target, and Crabtree certainly creates separation as well as any wideout in the league, but we don't have to travel back far in time to see just how valuable Boldin is to a playoff offense. He was QB Joe Flacco's top target during the Baltimore Ravens' Super Bowl run last year, making big-time, contested catches throughout the playoffs. So while Crabtree is the best at getting open, Boldin makes the difficult plays when everyone is covered, and he's a necessary outlet for Kaepernick.