Here's our weekly look at how the races for national seeds, regional hosts and at-large bids are shaping up. The NCAA doesn't release its official Ratings Percentage Index report until Tuesday afternoon, so we'll use the updated RPI rankings at WarrenNolan.com, whose Nitty Gritty Report includes detailed schedule breakdowns for every team in the top 105, plus all additional conference leaders.

We'll discuss at-large chances in a bit, but let's start with a look at which teams are on track to earn national seeds and which are on track to host regionals after the first 14 weeks of the season:

National seeds

SECURE TEAMS: Texas, Virginia, Arizona State, Florida

ON THE BUBBLE (IN): Coastal Carolina, UCLA, Louisville, South Carolina

ON THE BUBBLE (OUT): Auburn, Georgia Tech, Cal State Fullerton, Arkansas, Texas Christian

Our eight national seeds remain the same from last week, but South Carolina's hold on one of the eight seeds loosened after it dropped a home series to Florida, its fourth series loss of the season and its second in the last three weeks. The Gamecocks are now essentially even with Auburn and Georgia Tech in the race for the eighth national seed, with Fullerton and Arkansas very much in the picture as well. There is very little difference between the credentials of the Gamecocks and Tigers, who are back-to-back in the RPI (Nos. 12 and 13, per WarrenNolan.com). South Carolina finished a game ahead in conference play and won the head-to-head series against Auburn in March, but the Tigers have been hotter down the stretch, winning five straight weekend series, including a road series at Arkansas and a road sweep of Mississippi. The SEC tournament will have to be the deciding factor. The Yellow Jackets and Razorbacks are a few spots ahead of both Auburn and South Carolina in the RPI, and Georgia Tech is in better position than Arkansas, which must leap over two teams that finished ahead of it in its own conference. Tech's credentials are very comparable to Auburn's and South Carolina's, and a strong ACC tournament performance could easily give the Jackets the nod over both.
UCLA and Louisville improved their position with sweeps this weekend. The Cardinals needed to overcome Connecticut and win the Big East to feel good about their chances, and they surged to the conference title on the final day of the regular season. The Bruins have rebounded nicely from a series sweep at the hands of Arizona State three weeks ago, and they have emerged as the clear No. 2 team in the loaded Pac-10, a nice complement to their robust RPI (No. 6).

Regional Hosts

SECURE TEAMS: The 13 teams listed in the national seeds discussion

ON THE BUBBLE (IN):  Oklahoma, Miami, Florida State

ON THE BUBBLE (OUT): Connecticut, Vanderbilt, Oregon, Clemson, Rice

The last host spot is very much up for grabs heading into the season's final week. One change from last week: Oklahoma surges past UConn after beating Arkansas midweek and earning a huge road sweep at Kansas to solidify its place as the No. 2 team in the Big 12. A mediocre conference record was the one thing holding the Sooners back from being a clear host for most of the season, but 15-10 looks a lot better than 12-10.

UConn did not do anything to worsen its position over the weekend, taking two of three from Seton Hall, but the Sooners simply passed the Huskies with a better week. Connecticut remains a strong hosting contender, as do Vanderbilt and Oregon, but none of those teams seems likely to host over Oklahoma now. That means they must compete with three ACC hosting candidates for two regionals.

Miami seems likeliest to host because of its strong RPI (No. 8), its good ACC record (20-10) and solid record against the top 50 (17-12). A look inside the numbers reveals that Miami has not proven itself to be an elite team, having lost all five series it has played against ranked teams, but the committee is unlikely to dig beyond the surface numbers. Florida State (No. 14) and Clemson (15) trail Miami in the RPI and finished two games behind the Hurricanes in the conference standings, so neither team figures to host at Miami's expense. The Seminoles and Tigers have very similar resumes; FSU was the more consistent team this spring, but Clemson made a statement by sweeping the 'Noles this past weekend to claim the ACC's Atlantic Division crown, so the team that fares better in the conference tournament is likely to get the nod.

Another option would be one of those teams—or Vanderbilt—earning the top seed in a regional hosted by Connecticut as a No. 2. The Huskies don't have a No. 1 seed resume, with just a 3-3 record against the top 50, but they have had a great season and would offer desirable geographic diversity as a host. If Oregon or Vanderbilt finishes strong, one of those teams could conceivably leapfrog both ACC teams and UConn to host, but that scenario seems a bit more unlikely. For now, we'll give the final hosting spot to Florida State based on its overall body of work, which includes series wins against Miami, North Carolina State and North Carolina, plus a 3-1 record in midweek games against Florida.

At-large Bids

There are 30 automatic bids awarded to conference champions, and these 18 are safe bets to be one-bid leagues:

America East, Atlantic 10, Atlantic Sun, Big Ten, Colonial Athletic Association, Horizon, Ivy, Metro-Atlantic, Mid-American, Mid-Eastern, Missouri Valley, Northeast, Ohio Valley, Patriot, Summit, Southwestern, Western Athletic, West Coast.

The automatic bids for the Ivy League (Dartmouth), MEAC (Bethune-Cookman), Patriot League (Bucknell) and WCC (San Diego) have already been claimed. Florida Gulf Coast (No. 43 in the RPI), stands a decent chance to earn an at-large bid if it fails to win its conference tournament, and Wichita State (No. 57) has an outside shot.

For this exercise, let's assume all 18 of those leagues get just one bid. That leaves 12 potential multiple-bid leagues. Below is a conference-by-conference look at which teams are on track to make the field, and which teams are on the wrong side of the bubble through 14 weeks.

The last four teams into our field of 64 are California, Liberty, Oregon State and Kentucky. Those are the teams most likely to be omitted if an upstart team wins a conference tournament in a league like the Big South, Mountain West, Sun Belt or Southern Conference.

Here are the changes from last week, in a nutshell:

IN: Baylor, North Carolina State, North Carolina

OUT: Texas Tech, Kansas, Southeastern Louisiana

Atlantic Coast Conference (8 total bids)

SAFELY IN: Virginia, Georgia Tech, Florida State, Miami, Virginia Tech, Clemson

ON THE BUBBLE (IN): North Carolina State, North Carolina

ON THE BUBBLE (OUT): Boston College

North Carolina State and North Carolina both helped themselves considerably with sweeps of Duke and Virginia Tech in their regular-season finales. The Wolfpack has overcome its atrocious nonconference strength of schedule to climb into the top 50 of the RPI, which nicely buttresses a resume that includes marquee series wins against Virginia and Georgia Tech. The 'Pack is pretty secure as long as it avoids an 0-3 showing in the ACC tournament, though two or more wins would give it more breathing room.

North Carolina still missed the conference tournament despite sweeping the Hokies to finish the regular season tied with Boston College for eighth place in the conference, because the Eagles won the tie-breaker by virtue of a win against second-place Georgia Tech, which swept UNC. North Carolina finished strong, winning three of its final four series including a road set against Clemson, and the committee likes teams that finished strong. The Tar Heels also rank 19th in the RPI, 25 spots ahead of Boston College. UNC's strong finish, combined with awful weeks for fellow bubble dwellers Kansas, Texas Tech, Tennessee and Kentucky, puts it in pretty good shape to become the first team to miss the ACC tournament and still snag an at-large bid.

Boston College, though, is in trouble despite making it to Greensboro. The Eagles are just 29-26 overall (compared to UNC's 36-20 mark) and are just 8-20 against the top 50, and they finished with a sputter, losing their last three series. BC needs to make a serious run in the ACC tournament to have a shot.

Big 12 (5 bids)

SAFELY IN: Texas, Oklahoma, Texas A&M, Kansas State

ON THE BUBBLE (IN):  Baylor

ON THE BUBBLE (OUT): Kansas

Three changes from last week: Baylor moves into the field of 64 after sweeping Oklahoma State; Kansas falls to the wrong side of the bubble after being swept by Oklahoma; and Texas Tech falls off the bubble entirely after being swept at Nebraska to drop to 27-27 overall. Also, Kansas State moves from the bubble to the "solidly in" category despite losing two of three to Texas A&M. That is more a product of other bubble teams falling off than of Kansas State doing anything to improve its position.

Baylor still finished below .500 in the league (12-13), but the Bears are in good shape in the RPI (No. 36) and finished strong, winning three of their last four series.

Kansas is trending in the opposite direction, having lost four of its last five series. The Jayhawks are a long shot, at best, for an at-large bid and must hope to win the conference tournament and the automatic bid.

Big East (3 bids)

SAFELY IN: Louisville, Connecticut

ON THE BUBBLE (IN): Pittsburgh

ON THE BUBBLE (OUT): St. John's

No change from last week. Pittsburgh finds itself on the bubble after dropping two of three against South Florida, but there is a lack of better candidates out there. And the Panthers do still have a series win against Louisville and a split against UConn, two series that carry their resume.

Big South (2 bids)

SAFELY IN: Coastal Carolina

ON THE BUBBLE (IN): Liberty

No change from last week. Liberty's resume is soft, with an 0-4 record against the top 50 and back-to-back series losses to end the year against Coastal Carolina and Winthrop, but again, which omitted bubble team is more deserving? The Flames really need a few wins in the Big South tournament, however, and cannot feel really good about their at-large chances unless they make the Big South title game.

Big West (2 bids)

SAFELY IN: Cal State Fullerton, UC Irvine

ON THE BUBBLE (IN): None

ON THE BUBBLE (OUT): UC Riverside, Pacific

No change from last week, other than the Anteaters moving from the bubble to the "safely in" category after a series win against UC Riverside, their fifth consecutive series victory.

Conference USA (1 bid)

SAFELY IN: Rice

ON THE BUBBLE (OUT): Southern Mississippi

No change from last week. Southern Miss is 70th in the RPI and must win the CUSA tournament and snag the automatic bid if they are to make regionals.

Mountain West (2 bids)

SAFELY IN: Texas Christian

ON THE BUBBLE (IN): New Mexico.

No change from last week. The Lobos are on the bubble with an RPI of 45th, but their opening-weekend series win at Texas gives their resume a signature series that no other bubble team can match.

Pacific-10 (8 bids)

SAFELY IN: Arizona State, UCLA, Oregon, Washington State, Stanford

ON THE BUBBLE (IN): Arizona, Oregon State, California

ON THE BUBBLE (OUT): Washington

California is in free-fall, having lost seven straight games, including back-to-back sweeps at the hands of Washington State and UCLA. The Golden Bears are the last team in our field of 64, and they get the nod over the likes of Boston College, Western Kentucky and Middle Tennessee State on the strength of series sweeps against Oregon State and Arizona. But their final final series at Oregon is a must-win.

The Beavers also need a strong week to secure their at-large spot. OSU did manage a crucial Sunday win at Arizona State, avoiding a sweep, but they remain just 10-14 in the Pac-10, tying them with Washington for eighth place. Oregon State probably needs to go 3-1 in its final four games against Oregon and Arizona to slide into regionals with a losing conference mark. Then again, with so few deserving at-large candidates at the back of the field of 64, maybe a 2-2 week would be good enough.

Like the Golden Bears, the Wildcats are tumbling, having dropped four straight weekend series, including a brutal home series against Cal State Bakersfield. But Arizona is still 20th in the RPI, and a series win at Oregon State would get it into the field easily. A fifth straight series loss might land the Wildcats on the wrong side of the bubble, but some other teams would need to emerge with more deserving credentials, and currently no such teams are on the horizon. Arizona's strong RPI, combined with series wins against Cal State Fullerton, Oregon and Washington State, should carry the Wildcats into regionals as long as they don't get swept by the Beavers.

Southeastern Conference (9 bids)

SAFELY IN: Florida, South Carolina, Auburn, Arkansas, Vanderbilt, Mississippi

ON THE BUBBLE (IN): Alabama, Louisiana State, Kentucky

ON THE BUBBLE (OUT): Tennessee

Tennessee had its at-large hopes crushed in the final weekend, getting swept by Alabama. LSU saved its regional chances with a series win against Mississippi State. Kentucky lost a horrible series at Georgia, but the Wildcats still are in position to get a bid despite missing out on the SEC tournament, thanks to a strong RPI (31st) and a 16-18 mark against the top 50. No other bubble team left out of our field comes close to that.

Southern Conference (3 bids)

SAFELY IN: College of Charleston, The Citadel

ON THE BUBBLE (IN): Elon

ON THE BUBBLE (OUT): Georgia Southern

The Citadel moves into the "safely in" category after sweeping a road series at Georgia Southern to win the SoCon's regular-season title. The Bulldogs rebounded nicely from back-to-back series losses by winning their final eight games of the regular season.

Elon won its final series against Samford to finish tied for third in the SoCon. The Phoenix's RPI (51st) places them right on the bubble, but their 7-7 mark against the top 50 and third-place finish in a solid conference should put them in a regional if they can win a game or two in the conference tournament.

Georgia Southern is in similar RPI range (No. 56), but an 0-12 record against the top 50 is a killer.

Southland (1 bid)

SAFELY IN: None

ON THE BUBBLE (IN): Texas State

ON THE BUBBLE (OUT): Northwestern State, Southeastern Louisiana,

Southeastern Louisiana's at-large hopes took a serious hit when it was swept by Northwestern State this past weekend. The Lions still have a chance, though, thanks to a decent RPI (No. 50) and a 4-3 record against the top 50, which compares favorably with teams like Liberty and Pitt. But it's hard to overlook that sweep in the last weekend, particularly because the Southland is not exactly a power conference.

Northwestern State has more wins against the top 50 (5-7) and finished a game and a half ahead of the Lions in the Southland, but an RPI of 63rd makes the Demons a bit of a long shot.

Texas State isn't exactly secure if it fails to win the automatic bid. The Bobcats are just 3-12 against the top 50 and have an RPI of 49th, but at least they won the Southland's regular-season title. That at least gives them a chance at an at-large spot if they make a run in the conference tourney but come up short.

Sun Belt (2 bids)

SAFELY IN: Florida Atlantic, Louisiana-Lafayette

ON THE BUBBLE (IN): None

ON THE BUBBLE (OUT): Western Kentucky, Middle Tennessee State, Florida International, South Alabama

No change from last week. Western Kentucky has an at-large-caliber RPI (40th), but a series win against MTSU in the final weekend does not erase three straight series losses in the previous three weeks, or a sixth-place finish in the Sun Belt. MTSU and FIU finished third and fourth, respectively, in the conference standings, but both have RPIs in the low 60s, so they'll need to do some serious work in the conference tournament. South Alabama tied FIU for fourth place and has a similar RPI, but three straight series losses to end the season submarine their chances.