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5 things: Vikings must be prepared for Philly's fast-break offense

Minnesota's defense must be at the top of its game in order to spring an upset of Philadelphia.

Officially eliminated from the playoffs at 3-9-1, the Minnesota Vikings face the final three games of the season beginning Sunday at the Metrodome against the Philadelphia Eagles.


Minnesota is left with nothing to play for but pride, and their jobs heading into a possible offseason of turnover. Philadelphia has won five straight games to propel itself into the middle of the playoff picture.


The past few weeks, even as the season has slipped away, the Vikings have stayed competitive and fought to add wins to their resume. Here are five things to watch as Minnesota tries to add another Sunday at home:


1. The NFL's top two running backs?


Adrian Peterson certainly holds the title of the league's best running back, but Philadelphia's LeSean McCoy is trying to steal it away. McCoy ran for 217 yards last week against Detroit in even snowier conditions than the Vikings faced at Baltimore. The big game propelled McCoy over Peterson currently on the league's rushing chart. McCoy now has 1,305 rushing yards this season to Peterson's 1,221 yards.


The biggest question might just be whether we'll see the matchup of the league's top two backs. Peterson returned to practice Friday and is trying to get ready to play Sunday with a sprained right foot. Add the foot injury to the groin injury Peterson has already been playing through and it would make sense to take it easy on the MVP running back with the playoffs out of the question.


But Peterson doesn't think that way.


Peterson will try and test the injury out again on Saturday and the decision on his status could lead all the way up to the game on Sunday. Backup Toby Gerhart is dealing with his own injury and hasn't tried to "burst" yet with his hamstring injury. Without either, the running back duties would go to Matt Asiata, fullback Jerome Felton and possibly a late addition to the roster.


Peterson and McCoy offer different styles. Peterson can run away from defenders, just like McCoy. Peterson can also make defenders miss, but Peterson relishes running over defenders and breaking tackles as well. McCoy specializes in stopping, starting and cutting on a dime (hence his Twitter handle  @CutonDime25) and leaving defenders flailing.


2. Someone to step up in the secondary


Coach Chip Kelly's offense is known for its pace and big-play ability and Minnesota will need someone to step up and stop the multi-dimensional attack with McCoy (who also has 40 catches), DeSean Jackson, Riley Cooper, and two pass-catching tight ends in Brent Celek and rookie Zach Ertz. Sunday is a bad time for the Vikings to be short-handed in the secondary.


Cornerback Josh Robinson is still out with a fractured sternum. Rookie Xavier Rhodes, the team's best cover cornerback in recent weeks, is doubtful with a sprained ankle. Making matters worse, Chris Cook showed up on the team's injury report on Friday with a knee injury. Already thin, Minnesota could be looking at a group of cornerbacks of Marcus Sherels, Robert Blanton, Shaun Prater and, again, maybe a late addition to the active roster. Blanton, a college cornerback who made the transition to safety in the NFL, has played the past few weeks as a cornerback again.


One positive is the likely return of playmaking safety Harrison Smith. Smith won't return to an immediate every-down role, but he will rotate with safeties Andrew Sendejo and Jamarca Sanford to add some help on the back end.


3. Big-play birds


Kelly's offense has been hitting at a high rate with McCoy, Jackson, Cooper and the tight ends. Philadelphia leads the league in rushing at 158.5 yards per game. The Eagles are also running at an average of 4.9 yards per carry, which also ranks first in the league. But the accomplishments go well beyond running the ball.


Philadelphia is first in the league in plays of 20-plus yards (80 total) this season and is first in passing plays of 20-plus yards (64). The Eagles are first in touchdowns of 20-plus yards (19 this season). Overall, they are second in the league in yards per play at a 6.19-yard average. Philadelphia has 16 runs of 20-plus yards this season and are third in total offense (409.3 yards per game). The Eagles can be efficient, but they take advantage of opposing defenses with big plays.


4. Another case of what might have been


The questions linger for Minnesota at quarterback and Foles coming into the Metrodome is another case of what might have been for the Vikings. Unfortunately, there are too many similar tales when it comes to Minnesota quarterbacks. There's the yearly reminder of passing on Green Bay's Aaron Rodgers not once, but twice in the 2005 draft.


The Vikings also have seen Russell Wilson, who was drafted in the third round in 2012, this season. Of course, Wilson was overlooked by every team, including some multiple times. Minnesota passed three times, including taking Robinson nine picks earlier. Later in that third-round (13 spots after Wilson) the Eagles nabbed Foles out of Arizona.


Foles has taken the job in Philadelphia from Michael Vick and likely won't be giving it back. Foles leads the NFL in passer rating this year with a 120.0 mark and he has thrown 20 touchdowns and just one interception. He didn't throw an interception in his first nine games this season. Over the past five games, the numbers are even more staggering. During the Eagles' five-game winning streak, Foles has completed 64.8 percent of his passes for 1,348 yards 14 touchdowns and one interception, which came last week. His 136.3 quarterback rating during that span is the seventh-highest by an NFL quarterback in a five-game stretch since 1960.


There are other circumstances in play. Christian Ponder was coming off just his first season in Minnesota and the team still hoped he would develop into the franchise quarterback after being a first-round pick a year earlier. Foles was no sure thing, of course. And Chip Kelly's work and offense with Foles probably deserves credit. But it's just another case of a quarterback that has looked to make a strong transition to the NFL that the Vikings missed out on.


5. A chance for Cassel


With the quarterback position still in flux, Matt Cassel gets another chance to start for Minnesota, his second straight start. It will be the second time this season Cassel is getting back-to-back starts. And more importantly, Cassel was chosen this week over a healthy Christian Ponder and Josh Freeman.


The numbers support Frazier's choice to stick with Cassel. The offense, particularly the passing game to support the running of Peterson and Gerhart, has looked more efficient with Cassel behind center. In his four games in which he's played at least a half, Cassel has thrown for 241 yards or more, the four biggest passing games by a Minnesota quarterback this season.


Cassel is the only Vikings quarterback to throw more touchdowns (seven) than interceptions (four) this season and he carries a team-leading 84.9 quarterback rating into Sunday's game against Philadelphia, which has the league's second-worst pass defense. Cassel has avoided sacks (3.6 percent of his dropbacks) compared to Ponder (10.2 percent). Cassel also has four turnovers to Ponder's 13.


Frazier gave no promises after Sunday's game on his starting quarterback, but Cassel might have a chance to stake a claim to the job on a temporary basis. Frazier said he wanted to give Cassel another shot after he threw for a Vikings' season-high 265 passing yards on Sunday in a loss at Baltimore in snowy and cold conditions. He was 17-of-38 passing and had two touchdowns and no turnovers.


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