As the NFL closes in on free agency and then the draft, we’re closing in on the end of the “In Depth” series of reports we started publishing in mid-January on each of the league’s teams.

In getting a look at most of the franchises through the eyes of people who observe them more closely individually throughout the season than I do, I’ve learned a lot about what went right and wrong for them in 2011. A handful of them stand out as teams that could really make a jump, if they catch a few breaks, in 2012.

There’s a lot of player movement that will happen between now and late-July when training camps open, but here are my early picks for who could become the surprise teams of 2012.

5. Carolina Panthers: Cam Newton made a believer out of many skeptics in 2011 and he made a believer out of teammates. Predicting that he will duplicate his 14 rushing touchdowns in 2012 would be a stretch. But with a real offseason and a year of experience, there is a likelihood that he’ll improve upon his passing stats, particularly if Carolina adds another weapon or two for him on offense. And the Panthers get several defensive linemen back from injuries that hurt the team’s ability to stop the run. I’m not sure this is a playoff team yet. But opponents of the Panthers will be in for a game this upcoming season.

4. Arizona Cardinals: After a 1-6 start, Arizona closed 7-2 to finish at 8-8. This accomplishment came with mediocre quarterback play from Kevin Kolb and John Skelton, leading many people to speculate this would be a good landing spot for Peyton Manning. Even without him, the defense was quite good in 2011. And Beanie Wells, who broke 1,000 yards despite injuries, will see competition from Ryan Williams. There are needs, particularly on the offensive line and at wide receiver next to Larry Fitzgerald. But four of the eight losses in 2011 were by four points or less. This team has momentum heading into 2012 and will be a team to watch.

3. Houston Texans: Houston will lose Mario Williams. That’s a given, according to most industry observers. But several guys stepped up to play well in his absence in 2011 and the team still went 10-6 and made the playoffs for the first time. In fact the defense was one of the league’s best. The improvement will come on offense, where Arian Foster likely will be healthy from the get-go. At quarterback, Matt Schaub will likely return. And if he doesn’t, 2011 third-stringer TJ Yates will likely be better prepared to run the offense than he was as a rookie. This is a team that is built for contending over the next few years.

2. Detroit Lions: This is another team built for long-term competitiveness. There are a couple need spots, including youth on the offensive line and a shut-down defensive back or two. But what could really make Detroit better is the return of running backs Jahvid Best (likely in some more limited role) and Mikel Leshoure. The Lions’ offense was largely spectacular through much of 2011 with less-than-stalwarts like Maurice Morris and Kevin Smith leading the run game. Give Matt Stafford another element to work with and this team becomes an even bigger threat.

1. Cincinnati Bengals: On the strength of rookies Andy Dalton and AJ Green, Cincinnati jumped back into relevance in 2011. Now, after years of being largely irrelevant, the team has an estimated $44 million in cap room and two first-round picks it can play with.

This is still a flawed team in many ways. And the team typically has not been a large player in free agency. But here’s a scenario to ponder. Cincinnati needs a second wide receiver and help on the interior line. Division rival Pittsburgh put a first-round tender on Mike Wallace, but the Bengals easily have the cap room to make him an offer Pittsburgh couldn’t match. And if you are trying to make a run, wouldn’t you rather have a proven commodity than someone selected with a late first-round pick?

Division rival Baltimore has guard Ben Grubbs. Cincy could make a run at both Wallace and Grubbs, dramatically improving their roster while putting dents in their two biggest rivals. They would still have cap room left over to fill other needs and they also would still have the second first-round pick left to use on solidifying another weak spot, perhaps in the defensive backfield.

Cincinnati’s run to the playoffs in 2011 was largely unexpected. But if they play their cards right in 2012 the Bengals could set themselves up to be a real contender for years to come.