The NCAA selection committee will release its current top 16 on Sunday on CBS at 12:30 p.m. ET. Committee chairman Bruce Rasmussen will give us the current top four seeds in each region and where they would be playing if the tournament started Sunday. 

The exercise gives the committee a chance to talk about their selection process and what is important and what is not in making these decisions. I will be part of the show again this season, helping to fill out the remainder of the projected bracket. But this has been a particularly tough week at the top of the bracket.

Home losses by Villanova to St. John's and Purdue to Ohio State have shaken up the order of the No. 1 seeds, but nobody dropped off the top line. Virginia, which survived a tough battle at Florida State, is back in the overall No. 1 spot. That spot is the Cavaliers' to lose now. They are approaching a relatively soft part of their schedule, at least by ACC standards. They do still have road games with Miami and Louisville.

Villanova has been playing shorthanded while Phil Booth recuperates from his injury, but the Wildcats were also without Eric Paschall against the Red Storm. Paschall is recovering from a concussion. Villanova still has road games left with Providence, Xavier, Creighton and Seton Hall, so they need to get healthy soon.

Xavier also got a challenge this week, coming back to win at Butler in overtime. The Musketeers passed Purdue for the No. 3 overall spot on the top line. Xavier also has a difficult schedule left, which is unavoidable in the Big East, but most of their tougher games will come at home.

Purdue blew a 14-point second half lead to lose on a Keita Bates-Diop put-back with two seconds left. The Boilermakers will travel to Michigan State on Saturday and likely be an underdog for the first time in quite a while and the last time in the regular season.  They can lose to Michigan State and be a No. 1 seed a month from now but would likely not be one next week.

Michigan State actually needs that game more. The Spartans have beaten only one team in the current bracket, which was a neutral-court win against North Carolina back on Nov. 26. The Spartans' standing in the polls is due to that gaudy record, but a poor strength of schedule and lack of quality wins have capped them for now.

The Pac-12 continues to cannibalize itself. UCLA won at Arizona on Thursday night to pick up its best win of the season and put a little distance between itself and the bottom of the bracket. Washington, which had been trending upward, took a big step back with a 25-point loss at Oregon. USC pushed itself closer to the edge of the bubble with a loss at Arizona State. The Trojans are the last team in the bracket this morning.