Bubbles of their own making

Losses to Columbia and Seton Hall have contributed to Villanova's bubble status. Kim Klement/USA TODAY Sports

With Selection Sunday just 18 days away, we have a clearer picture of which teams are on the NCAA tournament bubble -- and those teams are appropriately anxious. This is the time in the season when a game between Villanova and Seton Hall is a very big deal, even though those teams entered Monday's contest with Big East records of 9-6 and 2-13, respectively (Nova lost).

Today I want to take a closer look at four of those anxious teams, and specifically I hope to shed some light on how exactly they landed on the bubble. At one time -- whether in the preseason, at some point over the past three months, or both -- all of these teams were considered worthy of an at-large bid, but now that worthiness is being called into question. What happened?

Next to each team I've included its current status, according to my colleague Joe Lunardi's latest bracket projection (updated Tuesday). Here are four nervous teams, and how they arrived at their present condition:

Villanova Wildcats

Bubble status: Last four in

At the moment, Lunardi has the Wildcats in the field of 68 -- but only just barely, and a lot can change between now and Selection Sunday. Meaning Jay Wright's team is in a precarious position.

And you can make a pretty good case that a team with wins over Louisville, Syracuse and Marquette should not find itself in a precarious position. Indeed, one of the underreported stories of this college basketball season has been the fact that Villanova has made a significant improvement on defense. The Cardinals and the Orange tend to get all the attention when it comes to D in the Big East, but it's actually Nova that's limiting conference opponents to the lowest 2-point shooting percentage (40.9) of any team in the league. So why is an at-large bid not yet nailed down?