Two NFC North rivals and playoff contenders meet Sunday afternoon when the Detroit Lions take on the Minnesota Vikings at Mall of America Field in Minneapolis.
Here are five storylines to follow:
1. The last time these teams faced each other — Sept. 30 in Detroit — the Lions' special teams were in total disarray. The difference in the Vikings' 20-13 victory was a touchdown on a kick return and a touchdown on a punt return.
The Lions, however, appear to have plugged those holes on special teams since giving up four scores in two weeks. In the last four games, they've allowed an average of 6 yards on punt returns and 20.4 yards on kick returns.
That's quite a turnaround considering the NFL averages this season are 9.2 yards per punt return and 24.2 per kickoff return.
"They're not even the same special teams by any means," Minnesota coach Leslie Frazier said. "They're so, so much better as a group across the board."
To which Lions coach Jim Schwartz quipped, "I would hope so."
The next step for the Lions is to improve their kick- and punt-return production. Return specialist Stefan Logan has been shaky in recent weeks, and he's putting the onus on himself to start making a difference.
"We've got to flip it now and get the return part rolling," Logan said. "I'm not worried about nothing else but to give the offense great field position. I know they're going to block for me. It's just catch and run, that's my plan."
2. The Lions have added a more efficient run game at times, giving them better balance on offense.
"They're running the ball well right now and we're not defending the run well right now," Vikings defensive end Jared Allen said.
In its last four games, Minnesota has allowed an average of 165.8 yards rushing. In the four games before that, the Vikings gave up 70 yards on the ground per game, including just 55 to the Lions.
In winning back-to-back games, Detroit has made five touchdown drives of 80 yards or more.
Asked how that type of ball-possession offense can benefit a team's own defense, Allen answered, "It's huge, just the fact that you can be fresh. Whenever your offense can stay on the field, it's awesome. You're eating up clock, you're taking a possession away from the other team. Having a run game, it helps your defense."
The Lions, it appears, finally might have a decent run game to help their injury-plagued defense in that way — they just have to prove it over time and against tougher competition.
3. Detroit went through its struggles early, losing three straight, only to bounce back and win three of its last four.
Minnesota started fast, but the Vikings are the one in trouble now, having lost two straight and three of their last four.
There should be a tremendous sense of urgency on their part.
"You'll have some lulls sometimes during a course of a season," Frazier said. "You've just got to be able to handle it and handle it the right way."
In a 16-game NFL season, there's not much time to get it right. That's what makes this game potentially so crucial for both sides.
Realistically, the season could be on the line for the Vikings. Their next two games are at Chicago and at Green Bay.
It's not that much different for the Lions. They've already lost to Minnesota once and the No. 1 tiebreaker for a playoff bid is head-to-head competition.
Sunday's winner is guaranteed nothing but a better opportunity to contend for one of the NFC's wild card bids. But for the loser, it's going to be a much tougher road to the playoffs.
4. Has any position coach in the NFL gotten more out of a bad situation in the first half of the season than the Lions' defensive back coaches?
They have two — Tim Walton and Marcus Robertson — working under defensive coordinator Gunther Cunningham.
The entire secondary was under fire for the way it fell apart late last season. Throw in all the injuries this year and it had the makings for a total disaster.
Instead, Walton, Robertson and Cunningham have somehow figured out a way to piece together a respectable, if not solid, group on the back end.
They've had to juggle the lineup constantly and even coached up rookie cornerback Jonte Green, a sixth-round draft pick, who has been the team's most improved player since the start of training camp.
"You can always talk about depth and talk about next man up," coach Jim Schwartz said. "It's a lot easier said than done, especially with all the different combinations of guys we've had out there.
"You don't get any prizes. It's our job to get it done every week, but it's certainly been a good job so far by those guys."
The secondary remains fragile and still could get exposed, but it's playing well enough to shut down Minnesota quarterback Christian Ponder, who is an absolute mess right now.
In his last three games, Ponder has completed 51.4 percent of his passes for an average of 124 yards, with two touchdowns and four interceptions.
5. Whether Vikings running back Adrian Peterson qualifies for Comeback Player of the Year is debatable because all he really missed was one meaningless game.
That's how incredible his comeback has been following surgery for a torn anterior cruciate ligament.
Peterson was injured on Christmas Eve in Minnesota's second-to-last game last season. Nevertheless, he was back and arguably as good as ever by this year's season opener.
Peterson leads the NFL in rushing with 957 yards in nine games. He's averaged 152.7 yards the last three games, including 182 last Sunday against Seattle.
"I have been amazed," Frazier said. "Just incredible when you consider the surgery that he had and how difficult the rehab was."
Allen said of Peterson: "He's a monster. The guy has such heart and such work ethic. He trained so hard. When he said he was going to be back, I don't think anybody doubted him."
Peterson rushed for 102 yards on 21 carries against Detroit in the first meeting. The Lions, however, held the Vikings' offense without a touchdown in that game.
INJURY REPORT
Minnesota's Percy Harvin, a multipurpose star, is officially listed as doubtful for Sundays' game. He hasn't practiced all week since sustaining an ankle injury last Sunday.
It would be a significant loss for the Vikings. Harvin ranks second in the NFL in combined yards with 1,347 in nine games (677 receiving, 96 rushing, 574 kickoff returns).
For the Lions, linebacker DeAndre Levy, who has missed the last two games because of a hamstring injury, is expected to return to the lineup. He is listed as probable.
Receivers Calvin Johnson (knee) and Titus Young (knee), defensive end Cliff Avril (back) and defensive tackle Corey Williams (knee) are all officialy questionable. Johnson practiced Friday for the first time this week and plans to play. Safeties Louis Delmas (knee) and Amari Spievey (concussion) remain out.
