SportsCenter's divisional analysis moves to the NFC North on Tuesday night (ESPN2, 7 p.m. ET). We've already discussed our most versatile players as well as potential breakout players, so let's give our television pals a pre-show primer on the biggest improvement (and regression) each division team made this offseason:

Chicago Bears: Enhanced comfort zone for quarterback Jay Cutler
In detail: The Bears fully committed to Cutler three years after acquiring him from the Denver Broncos. They finally gave him a full complement of promising receivers, most notably his all-time favorite in Brandon Marshall. Cutler will have his choice of big downfield threats, be it Marshall or rookie Alshon Jeffery, and Devin Hester has drawn rave reviews for his work within the team's new concepts. Coach Lovie Smith hired one of Cutler's favorite former coaches, Jeremy Bates, as quarterbacks coach, and offensive coordinator Mike Tice has liberally assimilated thoughts from Bates and Cutler into his scheme. For the first time the Bears feel like Cutler's team.
Biggest regression: The Bears' top four defensive players -- linebacker Brian Urlacher, defensive end Julius Peppers, linebacker Lance Briggs and cornerback Charles Tillman -- all got a year older without the team acquiring a potential heir at any of their positions. (Rookie defensive end Shea McClellin is projected to fill the Bears' spot opposite of Peppers.)

Detroit Lions: Insurance and a long-term plan at left tackle
In detail: The Lions mostly stood pat this offseason, making it their top priority to keep together a nucleus that earned a playoff spot three years after the franchise bottomed out at 0-16. They accomplished that goal by reaching contract agreements with receiver Calvin Johnson and linebacker Stephen Tulloch while franchising defensive end Cliff Avril. Retaining young players with room for growth counts as an improvement, but most notably, the Lions hatched a legitimate plan for the end of left tackle Jeff Backus' career. First-round draft choice Riley Reiff could replace Backus this season if necessary but could also get a year to develop. Regardless, it's a rare luxury for a team to have a legitimate succession plan in place at left tackle.
Biggest regression: It might not qualify as a step back, but the Lions didn't do much to improve a secondary that struggled for large portions of the 2011 season. Nickel back Aaron Berry will compete with free agent acquisition Jacob Lacey to start opposite Chris Houston, and the Lions appear set to give safety Amari Spievey one more chance to lock down a long-term job.

Green Bay Packers: Adding juice to their defensive front
In detail: As we discussed in May, the Packers devoted a large portion of their offseason to elevating the energy and competition along their defensive line. They hope to manage the playing time of nose tackle B.J. Raji more efficiently by calling on rookies Jerel Worthy and Mike Daniels, along with eventual contributions from Anthony Hargrove (eight-game suspension) and Mike Neal (four-game suspension). The Packers have also signed Phillip Merling, a former second-round draft pick of the Miami Dolphins, and veteran Daniel Muir.
Biggest regression: The Packers had near-ideal insurance at quarterback when Matt Flynn was their backup quarterback. Presumptive replacement Graham Harrell has extensive experience in the Packers' system and has been widely praised by coaches this offseason, but no one has suggested he is the equivalent of Flynn just yet.

Minnesota Vikings: A better situation for a young quarterback
In detail: Quarterback Christian Ponder will have a blue-chip left tackle in rookie Matt Kalil protecting his backside and two proven pass-catchers for mid-range passing in tight ends Kyle Rudolph and John Carlson. The Vikings have also added a receiver who can stretch the field in Jerome Simpson, who will be eligible to play in Week 4 after an NFL suspension, and might have unearthed a draft steal if Arkansas' Greg Childs is healthy. The offense is far from a finished product, but it is staffed much better at multiple positions than it was in 2011.
Biggest regression: The Vikings appear to have cast aside E.J. Henderson, their middle linebacker for most of the past decade. For now, that means they are hoping to make fourth-year player Jasper Brinkley their new starter. Brinkley played decently when he started four games as a rookie in 2009, but he missed all of 2011 because of a hamstring injury and coaches are waiting for him to turn it loose this spring.