Michigan State is still there, but we'll have to see for how long. The injury bug has bitten the Spartans. Adrien Payne hasn't played in a couple weeks because of a foot injury, and Branden Dawson suffered a stupid, self-inflicted broken hand that will sideline him for a month.
The other four have all struggled to some degree. It hasn't been so bad that any of them are in danger of missing the tournament, but building a top-seed level resume hasn't been easy.
Kansas is the closest to making the comeback. The Jayhawks have played the toughest schedule by an overwheling margin. The difference between their rating and that of and SOS No. 2 Alabama is .0768, which is roughly the same as the difference between the Tide and No. 79 Wake Forest. Early on, it looked like that was too tough a road for a young team, but since a home loss to San Diego State, the Jayhawks have ripped off five wins in a row, all against likely tournament teams.
Duke and Kentucky have been hit and miss. The Blue Devils lost to Kansas and Arizona outside the league, and picked up a win over Michigan, which looks a lot better now than it did at the time. In the league though, they have losses at Clemson and Notre Dame. Those aren't terrible teams, but certainly beatable for a team as talented as Duke.
Kentucky has been a home court hero, which is where they beat Louisville. The Wildcats' only away from home wins are over Providence in New York and at Vanderbilt. All four losses have come away from home, including most recently at Arkansas (the king of home court heroes). UK has four of its next six on the road.
Defending champ Louisville spent a lot of time near the bottom of my bracket, based primarily on a low number and quality of good wins. Before the win at Connecticut, their best wins were at home over SMU and Southern Miss. Neither of those teams are sure at-large quality, and they only had one other top 100 RPI win (Missouri State - also at home). So, the win over the Huskies filled a couple big holes in the Cards' resume, but there's still quite a way to go before they are contending for a No. 1 seed.