Bracket Watch: The NCAA Tournament bubble is changing by the day

The mix of bubble teams in play for the last few spots in my field has actually changed quite a bit -- on both sides of the cut line -- over the past week or so. Here, now, a little update on the contenders.

Trending up: Michigan State, Vanderbilt, Illinois.

The 18-11 Spartans are close to a lock at this point after beating Wisconsin over the weekend. The 16-13 Commodores have surged from below .500 a few weeks ago to one of my last four in. And the 17-12 Illini, largely forgotten all season, have moved into my first four out after improving to 7-9 in conference.

Trending down: USC, TCU, Kansas State.

The Trojans, once 21-4, are suddenly on shaky ground after four straight losses, most recently to 14-16 Arizona State. The 17-12 Horned Frogs and Wildcats had been in my field all the way up until this edition. Both are now 6-10 in the Big 12.

Wild card: Illinois State.

While Wichita State is likely in regardless of whether it wins this week's Missouri Valley tournament, 25-5 Illinois State is harder to predict. A Jan. 14 win over the Shockers is essentially its entire resume. The Redbirds got my last at-large.

A reminder: Selection Sunday is March 12, and the tourney begins March 14. The Final Four is April 1-3 in Phoenix.

* -- Denotes projected conference champion, automatic berth

This edition's bracket is Midwest vs. West and East vs. South in the national semifinals, based on the order of my No. 1 seeds.

BRACKET WATCH

LAST FOUR BYES:

LAST FOUR IN: Vanderbilt, Syracuse, Wake Forest, Illinois State

FIRST FOUR OUT: Cal, Illinois, TCU, Kansas State

NEXT FOUR OUT: Ohio State, Rhode Island, Tennessee, Georgia

MULTIPLE BID CONFERENCES: ACC (10), Big Ten (7), Big East (7), Big 12 (5), SEC (5), Pac-12 (4), A-10 (2), American (2), MVC (2), WCC (2)