There's something rotten in the state of North Carolina. (Bonus points if you caught the Shakespeare reference.) Now, there's no need to panic - they are still 21-2, and at 15-5 ATS they are right near the top of the heap for betting success. It's just that the team that looked like they were virtually unstoppable at the beginning of the season suddenly looks mortal. They have lost twice in their last five games, and both times it was at home. They are just 3-3 ATS in their last six, and they needed overtime against Florida State to put away an opponent that had no business being even remotely close. There have been other glitches since the beginning of the new year, too - they needed overtime against Clemson, and they only barely squeaked past Georgia Tech. Good teams have had mid-season down periods and turned it around when it mattered, so it can and likely will get better. As a bettor, though, this kind of a downturn for an otherwise reliable team can be costly and confusing. Here's a look at what brought it on and how long it might stick around.

General lethargy - The Tar Heels were flying high and fast earlier in the season, but they have lost some of their zip since then. If you caught any of the Boston College game last week you know how frustrated Roy Williams is about the tempo of his team - he pulled a five-person switch. That was an attempt to get the attention of the starters, and to try and get some much-needed production off the bench. That was how he felt in a game that they ended up winning by 22, so you can imagine how thrilled he was when his boys lost by 11 to Duke. If The Heels don't rediscover their passion then the year could be shorter than they hoped.

Point pain - It can't be much of a surprise that North Carolina couldn't hang with Duke given that they were scraping the bottom of the barrel to find a point guard to play. Starter and star Ty Lawson was sitting on the bench all night with an ankle injury. His backup was in much worse shape - Bobby Frasor will miss the rest of the year with a torn ACL. That left Quentin Thomas the best and only choice to run the offense. The previous game, against Florida State, Lawson only played four minutes. Before those two games Thomas was averaging less than two points and less than 10 minutes a game. Lawson shouldn't be out too long, but this experience has shown that the Heels are as vulnerable as any team in the country at the point.

Not quite good enough - The scariest thing about the Duke game from a North Carolina perspective is that they likely wouldn't have won even if Lawson was playing. On paper, Duke shouldn't be able to keep up with the Tar Heels, but it was the guys in baby blue who were consistently a step behind. You might have thought that Duke would spend too much effort trying to contain Tyler Hansbrough and that he wouldn't be able to keep up because of that constant double team. Instead, they just let Hansbrough have his way. His 28 points and 18 rebounds were both as much or more than his team expects from him on his best days, but Duke didn't care. They had the confidence that they would be able to overcome Hansbrough's dominance, and they just made sure that no one else did anything to seriously hurt them. The fact that an opponent can come into North Carolina with that kind of a swagger and be completely justified in feeling it is pretty much a sign of the apocalypse. At the very least, it is a clear sign that the Heels aren't playing as well as they should.

Defense - There are some bright spots, but for the most part the Tar Heels are not a team that that plays defense as well as they should. They have the foundation to build upon - they lead the country in rebounding margin. Other statistical categories don't match that rebounding prowess, though. They are outside of the top 100 in defending field goals, and 65th in defending the three. Against Duke, the shot defending problems came to the fore when Duke drained 13 threes. Their defensive efficiency rating falls way behind the other teams who have obvious claims on a potential Final Four spot, too. For a team that has so much else going for it, it's a concern that their defense is a step below ideal. It's why some games have been closer than they should be, and it's a serious contributing factor to their recent case of the blahs.