The Minnesota Vikings defeated the Detroit Lions in Week 4.
The Lions have won their last two and three of their last four. They're playing much better than the team the Vikings defeated 20-13 in Week 4.
Minnesota and Detroit both need this game badly. The winner stays out of the cellar of the NFC North, and the loser finds itself in the basement—maybe to stay.
Here are my 10 keys for Minnesota to win.
Percy Harvin suffered a sprained left ankle against the Seattle Seahawks on Sunday. His status for Detroit is up in the air.
This piece from Sporting News lists Percy Harvin as "extremely doubtful" for Sunday's game against the Detroit Lions.
If Harvin cannot go Sunday, it'll be a devastating blow to the Vikings offense. He leads the team in receptions (62), receiving yards (677), and he leads all wide receivers with three touchdowns.
He is the best in the game at what he does, which is being the most versatile offensive weapon.
Christian Ponder is struggling. He's struggled for the last four games with Harvin. It's tough to imagine him without his No. 1 target. It could be his worst performance yet.
If Harvin's not healthy enough to play, the Vikings should rest him, especially with a bye next week. But if he can, then they desperately need him.
Adrian Peterson leads the league in rushing with 957 yards.
At this point in the season, the Minnesota Vikings have one reliable option on their offense: Adrian Peterson.
As the passing game continues to tailspin into irrelevance, Peterson gets stronger by the week.
The Vikings need that trend to continue, especially with Percy Harvin's odds of playing Sunday decreasing by the minute.
Peterson leads the NFL in rushing with 957 yards. Of those, 458 came in the last three games (just over 152 yards per game).
He's back and better than ever. Detroit is 14th against the run (106.2 yards per game), which means Peterson should be good for 100 on Sunday.
Christian Ponder has thrown at least one interception in each of the past five games.
Inaccuracy has killed Christian Ponder over the last five games.
His completion percentage over that stretch has been 60.9 percent (98-of-161), which is beneath his season average of 64.1. A more telling stat is his completion percentage over the last three games: 51.4 percent (38-of-71).
What makes the low completion percentage more unbearable is the rate at which he's turning the ball over. He's thrown at least one interception in each of the last five games and two in three of them.
If Minnesota wants a shot to win, Ponder has to take care of the football. He's likely to be without Percy Harvin, which means his options will be even more limited.
Ponder has to be a game manager. Do nothing to lose the game, and hope Adrian Peterson busts a big run or a receiver breaks a few tackles.
Throwing the home-run ball wasn't Ponder's strength anyways.
Christian Ponder has been sacked 14 times in the past four games.
Over the past four games, the Minnesota Vikings have allowed 14 sacks. Over the past four games, the Vikings have lost three games.
Coincidence? I think not.
The Detroit defense doesn't present the game's most fearsome pass rush (18 sacks, 18th best), but it still features players like Ndamukong Suh (3.5 sacks) and Kyle Vanden Bosch (3.5 sacks).
Christian Ponder is struggling, and one thing an offense can do to help its struggling quarterback is keep him upright and keep him from having to fend off a pass rush.
Many of Ponder's sacks in this stretch have been because of poor decision making, but plenty have been the cause of regressed line play.
It's up to both to ensure he avoids as many hits as possible.
Kyle Rudolph has two receptions for 17 yards in the past three games.
To begin the season, it appeared that Kyle Rudolph was on his way to a Pro Bowl nod.
He had 25 receptions for 225 yards and five touchdown receptions in the first six games. Those stats put him on pace for about 66 receptions for 600 receiving yards and roughly 13 touchdown receptions.
Since then, he's caught two passes for 17 yards. That's unacceptable. And it's fitting that as Rudolph has fallen off, so has the passing game.
Rudolph has strong, reliable hands and can make plays with the ball. But he needs the ball to reach him.
Defenses have adjusted to him, and he deserves blame for his drop in productivity. But so does Christian Ponder.
With Percy Harvin unlikely to play, Rudolph becomes Minnesota's No. 1 receiver. That means defenses will key on him that much harder and Minnesota will key that much more on getting him the ball.
The Minnesota Vikings haven't won a turnover battle since Week 4.
While the Minnesota Vikings haven't been notorious thieves at any point this season, their ability to create turnovers and maintain possession has regressed heavily in the past four weeks.
What a surprise.
The Vikings haven't won the turnover battle since Week 4 when they were plus-one against the Detroit Lions. Since then, they have tied it but never won.
Turnovers are a key to winning in the NFL. Statistics show that the team that wins the turnover battle more often than not wins the game.
This key isn't a groundbreaking concept, but it'd take some pressure off the offense, especially if it's the defense wreaking havoc on the Detroit offense.
Matthew Stafford has improved his play in the last three weeks, averaging 300 yards per game with a 2-to-1 touchdown-to-turnover ratio.
While Matthew Stafford hasn't been the Matthew Stafford of 2011 in 2012, he's on the path to recovery.
Stafford has thrown for 263, 352 and 285 yards over the past three weeks. That averages to 300 yards per game. One game was against the Jacksonville Jaguars, the eighth-worst pass defense. The other two were against the No. 7 and No. 16 pass defenses.
Stafford's yearly numbers aren't terribly impressive (2,393 yards, eight touchdown passes, seven interceptions), but he's still very deadly with the ball in his hands while operating in the pocket unfazed.
The Vikings are the seventh-best pass-rushing team (24 sacks), but Detroit's line is among the top 12 for fewest sacks allowed (15).
If Stafford is allowed to sit back unblemished, then the Vikings will lose because he will find Calvin Johnson, Brandon Pettigrew and/or Titus Young open downfield.
Calvin Johnson is having a down year (48 catches for 767 yards and a touchdown), but he's still capable of torching defenses.
Like quarterback Matthew Stafford, Calvin Johnson's numbers are down.
The 6'5" receiver has 48 receptions for 767 yards with one touchdown. He has four games of 100 or more yards receiving.
Johnson, despite his low touchdown total, is among the game's most dangerous receivers. It came out Thursday that Johnson's been battling nerve damage, which has limited his ability to grip the football.
With Chris Cook out for the year with a wrist injury, the Vikings are without their largest cornerback. It'll be on a number of defensive backs to limit Johnson.
Make Titus Young, Brandon Pettigrew and any number of other receivers beat you.
The Lions have an unreliable running game, which means the Vikings can expect a heavy dose of vertical plays.
Chad Greenway and the Vikings defense have allowed over 100 yards rushing each of the last four games.
On the last slide, I pointed out that the Detroit Lions rushing attack is unreliable. It is the 22nd-rated attack (103.6 yards per game).
That doesn't mean it's incompetent. Mikel Leshoure rushed for 70 yards and three touchdowns during last week's 31-14 win over Jacksonville.
He's got 375 yards on the year and averages 4.4 yards per carry. He's competent, just not terribly dangerous.
But the way the Vikings run defense has played the last four games, anyone can be dangerous.
The passing attack of Detroit should be the focus, but if the run defense remains in its strainer-like state, then the Vikings are trouble. It's okay to allow the pass or run to beat you, but it's impossible to win when an offense can run and pass on a defense.
Leslie Frazier's offense is not designed to come from behind.
Of Minnesota's five wins, the Vikings scored the game's first touchdown in four of them. The lone game was in Week 1 against the Jacksonville Jaguars.
And again, that was the Jacksonville Jaguars.
In Minnesota's four losses, it scored first in three of them, but they scored the game's first touchdown only against the Seattle Seahawks.
If the Vikings can get the game's first touchdown, then that will rile up the home crowd, which will rile up the players and rattle the opposition.
Minnesota is reeling.
Regardless of what the players say, they have to be pressing. By scoring the game's first touchdown, that will leave the offense feeling good about itself and will allow the defense to have the joy of playing with a lead.
All of that will lead to a healthier state of mind for every player on the roster, which should lead to them all being able to give their best performance.