The NFL has a small imbalance problem. A gap has gradually opened between the AFC and the NFC, with the AFC winning more interconference games for three straight years. Last year, that gap became a chasm. The AFC went 44-20 against the NFC, and two 8-8 teams made the NFC playoffs while three different 9-7 teams had to stay home in the AFC. According to Football Outsiders’ Defense-adjusted Value Over Average (DVOA) ratings, which break down each NFL play based on situation and opponent, 10 of the top 11 NFL teams last year played in the AFC teams. The Philadelphia Eagles were the only exception.

For the imbalance between the conferences to be corrected, a few long-struggling franchises in the NFC will have to rise up in 2004. Here’s a look at the three teams with the best chances of doing just that.

1. Detroit Lions The Lions were the worst team in the NFL from 2001-04, going 16-48 over those four seasons. But there are encouraging signs for the coming season. All that losing has allowed the Lions to amass a roster filled with talented young players, and while the three wide receivers chosen with the past three first-round picks get the most press, the defensive players are the most important. Pass rusher James Hall and run-stopping defensive tackle Shaun Rogers are right in their primes. Outside linebackers Teddy Lehman and Boss Bailey each had strong rookie seasons; after Bailey lost last year to a knee injury, they take the field together for the first time this fall.

The offense has nearly all the pieces in place. In the final seven weeks of 2004, Kevin Jones led all NFL running backs with 830 yards. He averaged 5.4 yards per carry over that time, and no other back with at least 70 carries was above 5.1. Jones should do even better this season behind a line that added ex-Colt guard Rick DeMulling. Wideouts Roy Williams and Charles Rogers will start the year healthy, rookie Mike Williams provides a dangerous third option, and veteran Marcus Pollard is a significant improvement over Stephen Alexander at tight end.

The missing piece is quarterback, where Joey Harrington has been below average for three years and tends to wilt in the face of a pass rush. Veteran Jeff Garcia could steal his job by midseason, and it’s worth keeping in mind that Garcia’s off year in Cleveland looked a lot worse than it really was because he faced a particularly difficult slate of opposing defenses.

Detroit fans should be optimistic: With Green Bay declining, the only thing standing between the Lions and a division title is Minnesota’s experimental defensive transplant.

2 Arizona Cardinals The popular perception is that the NFC West is wide open, and the Cardinals finally have a good shot at the playoffs. In reality, Seattle is a much better team than most people believe, and the chances of the Cardinals taking that big leap forward aren’t that good. Still, the pieces are definitely in place for a patented NFL surprise if a few things fall right. In Arizona, as in Detroit, the highly drafted young receivers get the press while the improving defense actually gives the team its best chance of turning things around.

Arizona wants to run a vertical passing game featuring its imposing trio of wide receivers Anquan Boldin, Larry Fitzgerald, and Bryant Johnson. That sounds good, but it would also require a quarterback to throw the ball deep with accuracy, and it’s hard to believe Kurt Warner is that quarterback. Since suffering a thumb injury in 2002, Warner has struggled to recapture the magic of his peak years in St. Louis. He did manage to get the ball deep last year in New York, but not accurately. He holds onto the ball far too long, resulting in tons of coverage sacks and lots of fumbles. Last year Warner was sacked 39 times in half a season, the same number that all Arizona quarterbacks had for the entire season. When Eli Manning took over, New York’s ratio of sacks per pass play dropped in half.

If Warner can somehow drink from the fountain of youth, the Cardinals should have the defense to win their division. They dramatically improved their pass rush last season, improving from 32nd to 19th in sacks allowed per pass play; the better pass rush helped the secondary prevent long completions. The additions of free agent Chike Okeafor and rookie Daryl Blackstock will make the pass rush even stronger. The next step is improving at cornerback, which is possible if Antrel Rolle can adapt to the NFL more quickly than most other highly drafted cornerbacks.

3. Carolina Panthers It was just two years ago that the Panthers represented the NFC in the Super Bowl , so it might seem odd to include them on a list of long-struggling franchises. But 2003 was only the second winning season in Carolina’s 10-year NFL history, and the Panthers went just 7-9 last year.

There are numerous indicators that the Panthers will be the strongest challenger to Philadelphia this season. Carolina’s struggles were due in large part to an abnormal number of injuries to top players; the team’s top receiver (Steve Smith), top two running backs (Stephen Davis and DeShaun Foster), and second-best defensive player (Kris Jenkins) were all lost for the year by Week 5. Despite it all, the Panthers made a dramatic turnaround in the second half, winning six of their last eight games and nearly making the playoffs. The Panthers actually outscored opponents last year, 355-339, and their final three losses came by just a field goal apiece.

An even stronger indicator that the Panthers will improve in 2005 lies in last year’s third-down defense. It was pitiable, but that’s not going to be the case this year. Historically, a team that plays much worse on third downs than it does on first and second down will improve the following year. (Likewise, a team that plays much better on third downs will probably decline.) Based on our DVOA ratings, Carolina’s defense ranked fourth on first and second downs in 2004, but 30th on third downs.

Regression to the mean will do a lot to improve the Panthers on third down and personnel changes – the addition of free agent cornerback Ken Lucas, the departure of subpar nickelback Artell Hawkins, and the return of Jenkins – will take care of the rest. If so, expect the NFL’s interconference imbalance to get just a little less glaring.

Mr. Schatz is the editor in chief of FootballOutsiders.com and the lead writer of “Pro Football Prospectus 2005.”