As always, Jim Schwartz's Lions will live and die with their defensive line.
Though the team lost defensive ends Cliff Avril and Kyle Vanden Bosch this offseason, they have done an admirable job in signing Jason Jones and Israel Idonije while drafting Ezekiel Ansah with the fifth pick of the draft and Devin Taylor in the fourth round.
Losing Vanden Bosch was addition by subtraction, as the veteran proved last year that his best days were far behind him by only racking up 3.5 sacks despite playing in all 16 games.
The loss of Avril will hurt more, but his small stature made him a liability in the run game. Idonije, Jones, Taylor and Ansah all have better size and length that will make them more effective in defending the run than Avril was.
The signing of Idonije may have been the best move in an offseason full of them for the Lions, as Pro Football Focus' Neil Hornsby called it a "slam dunk win" for the team.
Idonije was one of the most underrated linemen in the NFL last season and had only three fewer quarterback disruptions than Pro Bowler Jason Pierre-Paul.
Ansah, too, has the chance to be an impact player right away for the Lions. He was one of the best players in this year’s draft and is blessed with freakish athletic ability for a man his size.
The presence of Pro Bowler Ndamukong Suh and budding star Nick Fairley at defensive tackle will ensure that Ansah and the other defensive ends get blocked one-on-one all season long.
If healthy, Suh and Fairley will almost certainly produce big numbers, and if some of the Lions’ new defensive ends step up, this could be one of the best defensive lines in the NFL.
Don’t be surprised if they rank in the top five in the league in sacks by the end of the season.
The Lions' defensive front will be greatly improved in 2013, but that will only help so much without a strong secondary to go along with it.
Fortunately for Lions fans, Detroit's secondary should be better this year than last.
The expected improvement is largely a result of the additions of safety Glover Quin and rookie second-round draft pick Darius Slay.
Though Chris Houston has been a solid performer for the Lions over the last three seasons, the team has lacked a consistent second cornerback to play opposite him.
The hope is that Slay can be that guy. He has the size and speed that teams covet in a cornerback, and the Lions have said he will be healthy when training camp starts following offseason knee surgery.
Quin, too, is a big addition and finally gives the Lions another safety to pair with Louis Delmas.
When healthy, Delmas is one of the better playmaking safeties in the league. Quin’s presence will allow him to roam around the field wreaking havoc, while Quin prevents the big plays that have haunted the Lions in years past.
Second-year players Bill Bentley, Jonte Green and Chris Greenwood should all see time in the secondary as well, as depth won’t be an issue for the Lions like it has in the past.
While the Lions secondary is far from elite, it is good enough that it should be able to capitalize often on the pressure that the team’s defensive line creates.
If there's any area of concern for the Lions' defense, it's at the linebacker position.
The Lions are set at middle linebacker with Stephen Tulloch ingrained as one of the most consistent players at the position in the entire league, but both outside linebacker positions are major question marks for this team.
DeAndre Levy will be the starter at on the weak side, but the other starting spot is still up for grabs.
Ashlee Palmer, Tahir Whitehead and Travis Lewis will compete to start at strong-side linebacker, with Palmer having the slight edge before camp, according to Tim Twentyman of DetroitLions.com.
The lack of talent at linebacker will keep the Lions defense from becoming one of the best in the league. Still, it won’t be enough to keep them from improving on last year.
In talking about Detroit’s defense, it’s important to note that some of the team’s struggles can be attributed to poor special teams play. Though they ranked near the bottom in the NFL in points allowed, they ranked in the top half of the league in yards allowed.
The Lions’ special teams units losing the battle for field position far too often can explain this.
After hiring John Bonamego, it's clear this year's Lions are attempting to make sure they don't have the same problems that last year's team had.
Chris Burke of Sports Illustrated said recently that the Lions' talent level this year lies somewhere between last year's nightmare team and 2011's playoff team.
With all due respect to Burke, however, I must disagree.
On the defensive side of the ball, the Lions' group this year is undoubtedly the best in recent memory, buoyed by improvements on the defensive line and in the secondary.
The Lions' defense has the unenviable task of going up against Aaron Rodgers, Adrian Peterson and Jay Cutler twice a year each. However, after many years of getting torched by these divisional foes, the team may finally be up to the challenge of defending them this year.