Playoff games are often decided by players that don't dominate the headlines during the regular season. Here are four X-factors that could do the unexpected on Wild-Card weekend.
Kenny Stills, New Orleans Saints wide receiver
It was the rookie's' fifth touchdown of the season and raised his yards per catch average to an even 20.0 -- the best in football. Yes, the fifth-round draft pick has been a pleasant surprise for Sean Payton.
The Saints must be on top of their game to keep up with the Eagles' explosive offense Saturday night. Stills has emerged as Brees' favorite deep target; the guy who stretches the defense and allows Jimmy Graham more room to do his thing over the middle.
Stills has the skill-set to wreck a gameplan. Expect Brees to take at least one shot -- and likely more.
-- Dan Hanzus
James Starks, Green Bay Packers running back
The Packers offense is no longer just about the passing game. Their offensive line has done a great job opening up big holes in the running game, and backup James Starks can take advantage. Starks, not Eddie Lacy, is Green Bay's healthiest back heading into Sunday's game against the 49ers. Starks might not run with the same toughness as Lacy, but he's been very decisive and explosive in a backup role this season.
Starks is averaging 5.5 yards-per-carry this season, easily his career high. He's picked up his play of late with 135 yards on only 21 carries in the last two weeks. He has five carries over 25 yards this season with three long scores. Starks has played the role of surprising playoff star before, leading the way in the Packers backfield in 2010 for a Super Bowl victory. Don't be shocked if he comes up big again.
-- Gregg Rosenthal
Griff Whalen, Indianapolis Colts wide receiver
Let's go for a super secret weapon here. Since Griff Whalen was re-signed off the practice squad three weeks ago, the Colts have yet to lose a game. The second-year player slid into the starting lineup and has helped Pep Hamilton's newfound quick-passing offense. Whalen snagged 15 catches for 157 and two touchdowns as a starter. His presence has helped open up T.Y. Hilton on the outside. In the Week 16 meeting against the Chiefs, Whalen had the best game of his career, catching seven passes for 80 yards.
With the Chiefs attention still on Hilton and tight end Coby Fleener over the middle, Whalen will play a big role out of the slot Saturday. He'll provide Andrew Luck a reliable target to keep the chains moving on third down, and will have analysts comparing him to Colts slot receivers of yore.
-- Kevin Patra
Danny Woodhead, San Diego Chargers running back
We heard the Danny Woodhead whispers when he signed with San Diego: He's just a product of the Patriots system, a fluke who won't translate elsewhere. He's shut 'em all up in 2013. Woodhead has thrived in Mike McCoy's offense, hauling in 76 catches out of the backfield, second to only Pierre Thomas. His 605 yards and six touchdowns through the air are both career highs, as are his 106 rushes at four yards a pop.
We saw it right away in the preseason, when Rivers showed early chemistry with Woodhead, pegging him on wheel routes and patterns out of the backfield that suited the runner's quickness and surprising elusiveness.
More importantly, instead of clogging up a backfield-by-committee, Woodhead has served as the perfect complement to Ryan Mathews. He's an ideal third-down back to Mathews who, meanwhile, has enjoyed the best season of his career. These two backs can attack defenses in different ways and Woodhead is a contributing factor to the rebirth of Rivers.
-- Marc Sessler