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Five things you need to know about the Lions:

1. The Lions will be solid on offense this season: That conclusion seemed evident after viewing the team's impressive collection of offensive skill players, from receivers Calvin Johnson and Nate Burleson to tight ends Brandon Pettigrew and Tony Scheffler to running back Jahvid Best. All are blessed with playmaking abilities and, to various degrees, are threats to score at all times. Offensive coordinator Scott Linehan likes to throw the ball downfield and has commanded high-scoring offenses in Minnesota and Miami. If quarterback Matthew Stafford can make the second-year jump many expect, this offense will have firepower.

2. The defense is going to need every bit of that firepower: There is no doubt the defense is much improved following the additions of Ndamukong Suh, Kyle Vanden Bosch and Corey Williams. But the linebackers and secondary are largely untested and, in some cases, the result of patchwork personnel work. Linebacker Julian Peterson and safety Louis Delmas are the only proven players among the seven who will start between the two positions. Even a good pass rush gets stymied regularly, and when that happens, it's hard to imagine the players behind the line picking up enough slack. If they do, go ahead and name coach Jim Schwartz and defensive coordinator Gunther Cunningham the NFL's co-magicians of the year.

3. Concerns about the Lions' offensive line have faded: During their 0-16 season in 2008, the Lions' offensive and defensive lines seemed equally inept. The team, however, clearly didn't agree. It overhauled the defensive line last winter but made only one move on the other side, acquiring Rob Sims from the Seattle Seahawks to fill a long-standing hole at left guard. They've also staged a competition at right tackle between Gosder Cherilus and Jon Jansen, but for the most part the Lions appear to trust the players they have in place. It's an important leap, considering the importance of protecting Stafford and the team's $41.7 million investment in him. Center Dominic Raiola and left tackle Jeff Backus aren't always fan favorites, but they remain fundamental building blocks of this offense.

4. Stafford must lower his interception total: The only reason his 2009 interception rate didn't get more notoriety is that he played in only 10 games. But Stafford still threw 20 over that span, which projects to 32 over a 16-game season. No matter who was at fault for those mistakes last season, Stafford can't be the quarterback the Lions need him to be if he's involved in that many turnovers. Schwartz believes the frequency will decrease as the Lions improve the team around him, and that's true to an extent. But Stafford concedes he also must work on patience and recognizing that not every play is going to gain 25 yards. Sometimes, you throw it away and live to play another down.

5. The Lions need safety Louis Delmas to be a beast: That's a particularly tall order for a player who missed most of the summer because of a two-month-old groin injury. But given the uncertainty surrounding him in the defensive backfield and even at linebacker, Delmas is one of the Lions' few known quantities. He is a ferocious hitter with a competitive attitude and enough speed to stay with most receivers in coverage. There is widespread disagreement about the importance of safeties in the NFL, but make no mistake here: Delmas' role in Detroit is huge.

-- Kevin Seifert, ESPN.com