The health of Lions QB Matthew Stafford is a question mark going into Sunday's game against the Vikings. (US Presswire)

Vikings at Lions -- Week 4

Where: Ford Field, Detroit (FieldTurf, Indoors)

When: Sunday, 1 p.m. ET (FOX)

Spread: Lions by 4.5

2012 records – Lions (Overall: 1-2, NFC North: 0-0); Vikings (Overall: 2-1, NFC North 0-0)

Past results: Two most recent meetings -- September 25, 2011: Lions 26, Vikings 23 (OT); December 11, 2011: Lions 34, Vikings 28. Series record: Minnesota holds a decided 66-33-2 lead in the series dating back to 1961. Detroit has won the last three games, however, and 20 of the Lions’ 33 wins in the series have come at home. Detroit is 3-7 against Minnesota at Ford Field.

What matters: In a word: Winning. Detroit’s Week 3 loss to a Titans team they should have beaten won’t help their playoff chances, and a loss to the Vikings Sunday would send Detroit to the bye week with a dismal 1-3 record with two losses to beatable teams.

The Lions need an improved performance from their defense if they want to get a key divisional win. Detroit’s secondary allowed three touchdowns of 60-plus yards in Week 3, and the defensive line failed to sack Titans’ QB Jake Locker despite the fact that Tennessee’s offensive line was dealing with several injury issues. That can’t happen against a Minnesota team riding a wave of confidence after an unexpected win over the 49ers last week.

The Lions face a Vikings team Sunday that's built to exploit all of the defense’s weaknesses. Lions coaches have praised the development of second-year Vikings quarterback Christian Ponder, whose patience in the pocket belies his youth. Through three games, Ponder has yet to throw an interception, and he has proven adept at finding holes in coverage. Lions’ DBs must do a better job of staying with their receivers to limit Ponder’s impact.

Detroit has faced one of the NFL’s marquee running backs in every game so far this season, and Sunday is no exception. Adrian Peterson told Lions’ reporters that he’s not yet 100 percent following his December, 2011 knee surgery, but his 4-yard per carry average has helped Minnesota to the league’s fourth-best rushing offense through three games. The Lions have used pressure from their outside linebackers and a defensive scheme designed to funnel rushers inside to stop Rams’ RB Steven Jackson and Titans RB Chris Johnson this season. Expect more of the same game plan Sunday against Peterson, who is at his most dangerous when he breaks containment and finds space.

Detroit’s offense produced its most balanced performance in recent memory last week. RB Mikel Leshoure rushed for 100 yards on 26 carries, and his power rushing style opened holes for the passing game in the second half. While Detroit’s offense was able to post 41 points against Tennessee, the Lions must do a better job of getting WR Calvin Johnson involved early in the game. Johnson was targeted just two times in the first half against the Titans, compared with 10 times after halftime. His added involvement in the second half helped spread Titans’ defenders sideline-to-sideline.  Look for Detroit to try to get Johnson involved early -- and often -- Sunday.

Who matters: Matthew Stafford’s health is a major storyline heading into Sunday’s game. Stafford was forced to leave Detroit’s Week 3 loss to the Titans with a hip injury, and he was held out of Wednesday’s workout. He has practiced for each of the last two days and is listed as probable on Detroit’s official injury report, but the Lions say they won’t make an official decision on his status until Sunday. Jim Schwartz says he’s confident in backup quarterback Shaun Hill’s ability to lead the team, but there’s no hiding the fact that the Lions are a different -- and more explosive -- team when Stafford’s on the field.

Sunday’s game will also be a major test for DTs Sammie Hill and Nick Fairley, who will fill in for Corey Williams. Williams was ruled out for Sunday’s game after having knee surgery Tuesday. The loss of his inside presence and potent pass rushing skills will be a blow for the Lions’ front four. Hill’s performance this season has impressed Lions’ coaches, and he looks set to start in Williams’ place. The fact that Hill could start over 2011 first-round pick Fairley may surprise some fans, but it’s worth noting that defensive coordinator Gunther Cunningham has described Fairley’s play this season as inconsistent. Williams’ absence leaves Detroit with just three healthy DTs, so conditioning could be a factor late in the game.

Key matchups:

Lions O-Line vs. Vikings DE Jared Allen -- Allen has made a habit of having highlight-reel games against the Lions, and Detroit will devote a considerable amount of attention to stopping him. Look for left guard Rob Sims to help tackle Jeff Backus limit Allen’s impact. The downside to Sims’ possible role in double-teaming Allen is that Kevin Williams has also had success against the Lions’ interior linemen throughout his career. The Lions’ O-line has allowed just four sacks this season, ranking them third in the league in pass protection. To win Sunday, Detroit must keep the quarterback clean.

Vikings WR Percy Harvin vs. Lions back seven -- Harvin’s team-leading 10.3 yards per catch this season have been impressive, and he’s a difficult matchup for the Detroit for multiple reasons. First, Harvin is a true dual threat. In addition to his receiving numbers, Harvin has eight rushes for 42 yards (5.3 ypc). Don’t be surprised if Minnesota mixes in some designed runs for Harvin to test the entire Lions’ back seven.

Injuries of note: Detroit listed the following players on its injury status report for Sunday’s game: Out: DT Corey Williams (knee) Doubtful: S Louis Delmas (knee) and LB Travis Lewis (quad) Questionable: LB Justin Durant (back), Leshoure (groin), TE Tony Scheffler (calf) and S Amari Spievey Probable: T Corey Hilliard (elbow), DE Lawrence Jackson (calf), WR Calvin Johnson (ankle), Sims (knee), Stafford (hip) and WR Titus Young (knee).

Inside stuff: Leshoure’s rushing performance turned heads in his Week 3 debut, but second-year RB Joique Bell is slowly working his way into a bigger role. Bell has added special teams’ skills to his resume for the first time in his career, and Jim Schwartz called him an ideal short-yardage back -- especially in late-game situations. Don’t be surprised to see his role increase as the season goes on.

Connections: Sunday’s game marks Vikings’ FB Jerome Felton’s return to Ford Field for the first time since Detroit released him before the 2011 season. Felton spent three seasons in Detroit, appearing in 42 games. Two current Lions players will face their former team Sunday. Quarterback Shaun Hill and WR Nate Burleson spent two seasons together with the Vikings. They were coached in Minnesota by current Lions’ offensive coordinator Scott Linehan, who held the same position with the Vikings from 2002-2004.

Stat you should know: Detroit’s offense ranks third in the NFL in points per game, but the unit has been positively stagnant in the opening half. Of the Lions’ 87 points this season, 62 -- or 71 percent -- have come after halftime. If the Lions can put points on the board early Sunday, it will go a long way towards securing a win.

Record watch: Lions K Jason Hanson’s Hall of Fame worthy career continues to re-write both the NFL and Lions’ record books, and he could take another step towards an NFL mark Sunday. With seven points against Minnesota, Hanson will pass kicker John Carney (2,062 points) for third place on the all-time scoring list.

Looking ahead The Lions head to the bye following Sunday’s game, and the rest couldn’t come at a better time for a team with several nagging injuries. Detroit’s schedule following the bye is difficult from a travel and talent standpoint. They face a pair of difficult trips to Philadelphia (Week 6) and Chicago (Week 7). The back-to-back road dates following the bye place a greater premium on going into the bye with a 2-2 record.

Prediction: Lions 31, Vikings 24

Follow Lions reporter John Kreger on Twitter at @CBSLions and @JohnKreger.