Four Downs: NFC North

by Mike Kurtz

Chicago Bears

Biggest Hole: Interior Run Defense

In the 10 years between 2003 and 2012, Chicago boasted a top-10 DVOA defense seven seasons, a top-5 defense in five of those, and led the league outright in DVOA twice. (DVOA is Football Outsiders' defense-adjusted value over average metric, explained here.) The 2012 Bears defense led the league with -26.8% DVOA, the team's best performance in our 25 years of data going back to 1989. (Better defense is negative, not positive, because it is preventing scoring.)
Last year, the defense disintegrated. The 2013 Bears defense languished near the bottom of the league with a 8.6% DVOA, the team's worst performance over that 24-year span. After a ten-year reign of terror, and absent Lovie Smith and Brian Urlacher, the Monsters of the Midway were decisively vanquished.

By the end of the season opponents had learned there was no reason to ever pass against the Bears' horror show of a rushing defense, a unit ranking second-worst in the league in Adjusted Line Yards (4.45), and worst in the league in Second Level Yards (which measures the run-stopping ability of the linebacking corps). While defensive ends Julius Peppers and Shea McClellin were merely uninspiring against the run, the major headaches came up the middle, as defensive tackles Corey Wootton, Stephen Paea and Landon Cohen were gashed for the worst ALY in the league between the tackles when they were actually healthy enough to be on the field. Backup linebacker Jon Bostic did not help and was often lost in space on run support.

Unfortunately for Bears general manager Phil Emery, there are no easy fixes for this quagmire. The ends and outside linebackers played reasonably well considering their age (Julius Peppers, Lance Briggs, James Anderson) or their lack of experience (McClellin). McClellin should get better, but Peppers, Briggs and Anderson are on the downward slope of their career arcs. Bostic has potential, but it's too early to pencil him in at Mike, especially after a disappointing rookie campaign. Wootton, Anderson and two starters up the middle who missed significant time, middle linebacker D.J. Williams and defensive tackle Henry Melton, are all free agents this offseason. The cash-strapped Bears have to hope they can swing the low but significant outlay on Williams while shoring up both defensive tackle and linebacker through the draft as they plan ahead. Chicago is in a good position to get a potential impact tackle like Tim Jernigan or Louis Nix near the middle of the first round and draft projects at both positions in later rounds as the defensive retrenchment begins.

Detroit Lions

Biggest Holes: Running Back, Safety

Aside from a blip of respectability in 2011, the Lions' pass defense continues to underwhelm. More experience for young linemen Ezekiel Ansah and Nick Fairley should help take some pressure off Ndamukong Suh and lead to a more potent pass rush, but the team is talent-poor at cornerback and the release of Louis Delmas leaves them with a hole at safety. While there is a large pool of free agent safeties available, the few exciting names like Jairus Byrd come with too large a price tag for a team that just cut Delmas and Nate Burleson to free up cap space. Considering the organization's history with the secondary and financial concerns, Detroit could be well served by looking at cheaper, medium-risk, medium-reward options like Ryan Clark or Chris Clemons while adding the ball-hawking coverage safety Haha Clinton-Dix with the 10th pick to add depth and help generate turnovers out of the nickel in passing situations.

The biggest issue with Detroit's offense is that it all must flow through Matthew Stafford, who is maddeningly inconsistent to the tune of a 59.1 completion percentage (worse than Mike Glennon) and an extremely underwhelming QBR of 52.5, sitting right above Carson Palmer at 20th in the league. The Lions' offense is one-dimensional and will not find consistent success unless they establish some semblance of a running game. Detroit has a fairly talented offensive line, sporting a solidly above-average 3.95 ALY and genuinely impressive 76 percent success rate in power (short yardage) situations. Despite this, former undrafted free agent Joique Bell managed barely above-average production on a per-play basis at 2.0% DVOA. The committee's greater half, Reggie Bush, produced at essentially replacement level as a running back. Both players were excellent as receivers, but that's partly a product of Stafford and the Detroit scheme. Over the last five years, nine of the 11 Detroit running backs with at least 25 targets in a season put up a positive receiving DVOA.

Andre Brown would be an ideal pickup, as he fits Detroit's strengths on the cheap, but Maurice Jones-Drew might better option if and when he and his agent sober to the low market value for a workhorse back from a bad team coming off an injury. Either back would give the team some breathing room to pick from the many talented tailbacks projecting as mid-second rounders.

Green Bay Packers

Biggest Holes: Defensive Line, Safety

The Packers' offseason revolves around the majestic orb of B.J. Raji. Last year, the veteran defensive lineman turned down an $8 million/year extension and expressed frustration at the lane-clogging role he predominantly played in 2011 and 2012, only to receive and squander opportunities playing on the end in 2013. Despite ample cap space available, the combination of headache, ineffectiveness and unreasonable salary demands could mean the Packers might not want the former Pro Bowler back in town for 2014.

Regardless of whether Raji stays, the defensive line is thin and likely to be thinner as the Packers try to improve on a rushing defense that ranked third-worst in the league in 2013. Stout run defense is critically important in Green Bay's 3-4 scheme because it plays to the linebackers' pass-rushing strengths; the Packers had an Adjusted Sack Rate of 8.1 percent in 2013, ranking fifth in the league, but failed to provide adequate run support. Green Bay's best case scenario is that Raji's price nose-dives to affordability, young linemen Mike Daniels and Josh Boyd turn their potential into performance, and Ryan Pickett stays healthy and productive. When the best-case is relying on two baby-faced linemen, a disgruntled and ineffective veteran, and a 34-year-old's health, your team has serious depth issues. The Packers under McCarthy have shown a clear preference to build from within and extend home-grown talent, so a big splash in free agency is unlikely. Fortunately, quality linemen like Ra-Shede Hageman and Louis Nix should be available late in the first round, and there is some chance the Packers will have a few options to mull as they try to avoid another stumble like last year's disappointing first-rounder Datone Jones.

The beneficiary of McCarthy's organization-first spending strategy is likely to be Sam Shields, who the coaching staff seems to believe will blossom into a shutdown corner any day now. Right or wrong, the team will not be looking at cornerback to shore up a suddenly leaky pass defense. After giving Morgan Burnett a large extension last year, Burnett failed to produce by any measure and will be an expensive anchor to drag going forward. M.D. Jennings, Burnett's partner in crime, is a restricted free agent and was so bad that there is no reason for the Packers to even make an offer. This is a deep draft for safeties and cornerbacks, so the Packers should be able to find some relatively polished safeties in later rounds, if they hold off early in an attempt to find some young impact talent on the line.

Minnesota Vikings

Biggest Offseason Hole: Quarterback

After years of toiling with quarterback projects and coaches' favorites while squandering the magnificent career of Adrian Peterson, the Vikings are exactly where they have been, absent their brief Brett Favre affair, for the better part of a decade. Minnesota gave third-year quarterback Christian Ponder almost two-thirds of last year's snaps and had only a 22nd-ranked 51.2 Total QBR to show for it. After adjusting for opponents, Ponder's -13.4% DVOA was even worse, finishing only slightly better than pick-six machine Matt Schaub. Ponder's replacement, Matt Cassel, was similarly ineffective. Josh Freeman was brought in post-Prescriptiongate -- but was quickly swept under the rug after being flattened by the Giants, against whom he managed only 190 passing yards on 53 attempts. In the end, it did not matter who was taking snaps for the Vikings; all three players were terrible.

In the past, Minnesota has responded to similarly dreadful production by waiting things out and giving the players another year to turn the ship around. Ponder is still on his rookie contract and therefore dead weight, but Freeman is an unrestricted free agent and the Vikings and Cassel share a mutual, $3.7 million option for 2014. Considering the extremely short rope the team afforded Freeman, it is unlikely he returns for another, even partial, year. Cassel should concern the Vikings faithful, as his pedigree still has some cachet and is exactly the kind of veteran trap the Vikings love to fall face-first into. Indications are that Cassel will decline the option, but he could still be brought back.

Instead, Minnesota should walk away, take their lumps with Ponder and look to the draft for a quarterback (or two). The Vikings are in an uncomfortable position, as Blake Bortles and Teddy Bridgewater will almost certainly be gone by Oakland's fifth pick, much less Minnesota's eighth. If the Vikings were a better all-around team, trading up with a truly talent-starved team like Cleveland or St. Louis might be an option, but the Minnesota defense is also mediocre and could use a depth infusion. Staying put could mean the Vikings find themselves with Fresno State quarterback Derek Carr. While eighth overall might be a reach for a 1-2 round talent, there is no team in the league with as gaping a hole as the Vikings suffer at quarterback.

This article previously appeared on ESPN Insider.