It may seem odd to voice concerns about a team that's ranked No. 1 in the nation in one poll, and a lowly No. 2 in the other. And, to be sure, a lot of observers (and not merely pollsters) seem unconcerned about Duke at the moment, even as Ryan Kelly continues to sit with an injured foot.
The Blue Devils have helped this mindset along, certainly, by winning their last five games (though that last one, a 62-61 victory at Boston College, was certainly a close shave). At 21-2 overall and boasting lofty ratings even in those perennially skeptical computer ranking systems (currently No. 2 in the BPI, and No. 6 at KenPom), this certainly looks like your standard-issue Duke team. And, sure enough, after an initial bout of wobbly play in Kelly's absence, Mike Krzyzewski's team appears to have pulled itself together in its new configuration. I have even heard the term "blessing in disguise" applied to Kelly's injury.
Sorry, I'm not buying it. I guarantee you Coach K would gladly do without this particular "blessing," because his team's performance has changed dramatically without Kelly, and not entirely for the better.
Here's why I'm skeptical of a Duke team that right now is being endorsed by pollsters and computers alike:
The Blue Devils owe their high rankings in part to good timing.
And I mean "good timing" in both the big picture and the small scale. In the big picture, this is not the strongest ACC we've seen in recent years. The league does rate out as slightly better than it was last season, but both seasons represent a significant dip in quality from what we were accustomed to seeing from the ACC up until about 2011. And while Miami is clearly a legitimate Final Four threat (and Virginia is likely being underrated), the rest of the league is not lacking for mediocre teams.
In the small scale, Duke's schedule fortuitously steered them into the very heart of all that mediocrity soon after Kelly went down. Granted, the Blue Devils had to play at Miami without Kelly, and the result was a humiliating 90-63 loss at the hands of the Hurricanes. But since that harrowing evening in Coral Gables, Coach K's men have reeled off wins against Maryland, Wake Forest, Florida State, North Carolina State, and Boston College.
So, sure, the Devils have shown me they can win at Wake and at BC without Kelly, and they can even beat a projected No. 7 seed like the Wolfpack as long as they get them at Cameron Indoor. In other words, Duke's a pretty good team. No one says otherwise. But No. 1 in the nation? Read on.
Even during the win streak, this D has been questionable.
I'm going to give Duke the statistical equivalent of a do-over and ignore the blowout at Miami entirely. Instead, let's start the evaluative clock immediately after that game.
Certainly the Blue Devils have left no doubt in my mind that they can score points without Kelly. During this 5-0 stretch Duke has recorded a remarkable 1.21 points per possession. Again, that didn't come against the strongest defenses in Division I by any means, but it's still a very impressive display of offense.
But the fact that Coach K's team has been scoring like crazy yet still saw two of these games come down to the final minute (at Wake Forest and at Boston College) flags an important point. Duke's defense has been just average during this current winning streak. Krzyzewski has long been a master of denying three-point looks to opposing offenses, and his defense is still doing just that, leading one to conclude that this wasn't among Kelly's primary responsibilities. That is the only glimmer of good news on defense, however.
I'm not the first person to point out that Kelly's absence has hurt Duke's defense, so allow me to update the current numbers on just how big that hit has been. Without Kelly in the lineup, the Blue Devils have allowed their last five opponents to make 51 percent of their shots inside the arc. Coach K's team is also forcing fewer turnovers while fouling more often.
Defense is Duke's wild card.
Mind you, I'm not harping on the Blue Devils' D because "defense wins championships," or because a certain level of defense is required for a trip to the Final Four. Different teams reach that goal in different ways, and plainly an offense with Mason Plumlee and Seth Curry is a very nice asset to have.
But the one constant among really good teams is that they're consistently better than their opponents on a per-possession basis. Right now it's far from certain that Duke will be able to say that against the nation's top teams. An opponent that's happy to attack the paint and that is built to get to the foul line -- Indiana comes to mind -- could hit the Blue Devils where they're most vulnerable.
Just last week I included Duke on my short list of teams that can win the national championship. In the eight days since I made that list, however, the Blue Devils have fallen into the "questionable" category. For the season Coach K's team is now outscoring the ACC by 0.12 points per possession.
It's not for lack of scoring that Duke's profile as a contender is changing before our eyes. The problem is defense, and as long as Kelly sits out the Blue Devils will continue to confront this same challenge.
A version of this article originally appeared at ESPN Insider .
John Gasaway is an author of Basketball Prospectus.
You can contact John by clicking here or click here to see John's other articles.