Offseason grades: NFC North

Minnesota Vikings

BETTER: The offseason started rough with the initial outcry surrounding the trade of wide receiver Percy Harvin to Seattle and the release of veteran cornerback Antoine Winfield. But the Vikings replaced both, signing wide receiver Greg Jennings away from Green Bay in free agency and later using the No. 25 overall pick in last week’s draft on Florida State cornerback Xavier Rhodes. Minnesota added two other first-round picks in Florida defensive tackle Sharrif Floyd and Tennessee wide receiver Cordarrelle Patterson.

The key for Minnesota this season will be how much progress Christian Ponder makes in his third NFL campaign.

As good as running back Adrian Peterson is, Ponder must produce more in the passing game for the Vikings to make a deep playoff run.

Detroit Lions

BETTER: After losing eight consecutive games to end last season, Detroit’s front office didn’t stand pat.

The Lions struck in free agency by inking running back Reggie Bush, free safety Glover Quin and versatile defensive lineman Jason Jones, while also re-signing two defensive starters in cornerback Chris Houston and linebacker DeAndre Levy.

Left tackle is still a concern after Jeff Backus retired. With the talent on his roster, Lions head coach Jim Schwartz is expected to produce a playoff team in 2013 or he may be out of a job.

Green Bay Packers

WORSE: Although the Packers have lost in the second round of the playoffs the past two seasons, Green Bay general manager Ted Thompson refuses to stray from his plan of building almost exclusively through the draft and re-signing his own talent.

The Packers did the latter by striking new big-money deals with their two most valuable players — quarterback Aaron Rodgers and outside linebacker Clay Matthews. Thompson is counting on two rookie running backs (Alabama’s Eddie Lacy and UCLA’s Johnathan Franklin) to better the ground game and first-round choice Datone Jones to make a quick impact as a 3-4 defensive end.

Thompson’s belief in developing his own talent and eschewing free agency will be put to the test in a division where Minnesota, Detroit and Chicago have made up ground during the offseason.

Chicago Bears

BETTER: In his second season as general manager, Phil Emery continued to put his touches on Chicago’s roster by addressing some of the weaknesses on a team that went 10-6 in 2012 but didn’t make the playoffs.

Martellus Bennett should be a huge upgrade at tight end while two new offensive linemen (ex-New Orleans left tackle Jermon Bushrod and rookie right guard Kyle Long) are instant starters. The Bears hope veteran free-agent D.J. Williams or second-round pick Jon Bostic can fill the shoes of iconic middle linebacker Brian Urlacher, who won’t be re-signed.

All of these moves, though, pale compared to the curious hiring of Marc Trestman away from the Canadian Football League as head coach to replace the well-respected Lovie Smith. Emery hopes Trestman can get more out of up-and-down quarterback Jay Cutler, who is entering the final year of his contract.