In honor of Princeton earning the first official invitation to the NCAA tournament, here is a look at the conferences that are likely to earn just one bid. But first, a few words on the top of the bracket.

Barring major upsets over the final three weeks, the top eight lines are going to be pretty clear-cut this season. There might be some movement among teams over the last two weeks of conference play, but the distribution is almost locked in -- three SEC, two ACC, two Pac-10, one Big 12. If Arizona State's appeal is denied and the Sun Devils are ineligible for regional play, the final national seed would likely be claimed by a third ACC team or Southern Miss.

The other competition is for the final two hosting opportunities. With Fresno splitting each of its past two WAC series, the Bulldogs are on the outside looking in with a weak RPI. At this point, all five contenders are in the same geographic footprint. Rice and TCU earn the nod over Oklahoma, Arkansas and Oklahoma State, but the final 10 games of the season could have a major effect on that order.

America East: This is Stony Brook's (34-10, 15-2) race to lose, but a three-game set at second-place Binghamton (20-20, 12-4) could still factor in. There's added incentive in that series, as the regular-season champion gets to host the conference tournament.

Atlantic 10: It's a two-horse race between Charlotte (36-11, 15-6) and Rhode Island (29-17, 15-6). The 49ers won the regular-season series at home and own the tiebreaker over URI. The big race is for the last four spots in the conference tournament at Camden, as six teams are either 11-7 or 10-8 with six games remaining.

Big Ten: Michigan State (30-14, 13-5) broke a first-place tie by sweeping Purdue (30-16, 10-8) over the weekend. Every team in the conference has lost at least two conference series this season, so the tournament in Columbus should be a wide-open affair.

Big East: Last year, the conference earned three bids and hosted two regionals. Connecticut (34-13-1, 18-3) or St. John's (26-17, 13-7) could still earn an at-large bid with a strong finish, but only the winner of the tournament in Clearwater will be able to breathe easy on selection day. The Huskies have won 24 of their last 27 games and will likely burst another team's bubble if they win the regular-season title but lose in the tournament.

Big South: This is another conference that bubble teams will be watching with great interest in late May. Coastal Carolina (33-15, 17-4) has the résumé for an at-large berth and has gone 18-5 since the end of May. Liberty (29-19, 15-6) is trying to take the next step after missing last year's tournament despite winning 42 games, but the Flames have lost 11 straight to the Chanticleers.

Colonial: A wide-open race for the four-team tournament in Wilmington, with seven teams separated by three games. Old Dominion (24-20, 16-8) leads the pack after previous leader Delaware (26-22, 15-22), with the explosive offense of James Madison (31-16, 15-9) and tournament host UNC Wilmington (27-21, 15-9) just a game behind.

Horizon: Wright State (30-14, 13-5) currently leads the conference, has an easy finishing schedule and gets to host the conference tournament. Then again, the Raiders won the regular-season title last year but fell in the conference tournament.

Ivy: Princeton (23-22, 15-5) took care of business at home in the Ivy League championship series by taking two of three games from Dartmouth (30-12, 14-6). This will be the Tigers' first regional appearance since 2006.

MAAC: The lone blemish for Manhattan (26-16, 16-1) was an extra-innings loss at last-place Niagara. Marist (31-15, 9-9) dominated in nonconference play on its way to a top 20 RPI, but has struggled in conference play.

MAC: Kent State (32-13, 17-4) is looking for its third straight regional appearance and has an outside chance for an at-large bid with an RPI in the top 50.

MEAC: Bethune-Cookman (32-20, 18-0) has won all but one conference title since 1999, and was the only team in any conference to make it through conference play without a loss. No other team in the conference is above .500 overall.

MVC: This is a wide-open race in the conference that will christen postseason play at TD Ameritrade Park. Creighton (32-12, 10-5) leads the conference and has the best chance for an at-large bid, but just dropped a series at second-place Wichita State (30-22, 9-6). Missouri State (27-18, 8-6) and Illinois State (28-15, 8-7) also have strong squads.

MWC: TCU (33-14, 15-2) has experienced some bumps along the way attempting to return to Omaha, but should comfortably claim an at-large bid if the Horned Frogs fall short at the conference tournament in San Diego. Utah (25-16, 15-5) and UNLV (30-19, 7-10) are having solid campaigns but need the tournament title to reach the field of 64.

NEC: Quinnipiac's Kyle Birdsall threw a no-hitter against Monmouth on April 9 -- a game that proved to be a turning point for both teams. Since then, Monmouth (31-16, 22-6) has won 17 of 20 games to take control of the conference race, while Quinnipiac (15-32, 11-21) has lost 20 of 22 and will miss the conference tournament. The Hawks took the season series from their two main rivals for the title: Sacred Heart (27-20, 19-9) and Long Island (27-19, 18-9).

OVC: Austin Peay (25-19, 13-4) has jumped to the head of the class by claiming at least a split in each conference series. The Governors host second-place Southeast Missouri State (28-17, 10-6) next week, while defending tournament champion Jacksonville State (28-18, 9-8) lurks in third.

Patriot: The conference semifinals start this week, with top seed Navy (29-20-1, 12-8) hosting Bucknell (24-26, 10-10), while Army (19-24, 11-9) hosts Lafayette (18-28, 10-10). Navy didn't lose a single conference series, but expect the unexpected; the top seed hasn't won the automatic bid since 2007.

Southern: It seems strange to see the SoCon grouped with single-bid leagues, but despite some gaudy records, the conference isn't as strong as it has been recently (especially in RPI). Elon (33-18, 21-6) leads the conference and has a strong at-large résumé, but lost season series to No. 2 UNC Greensboro (27-18, 16-8) and fourth-place Georgia Southern (27-21, 14-10). The tournament will be wide-open, as College of Charleston (31-17, 15-9) and Samford (29-19, 14-10) also boast solid squads.

Summit: Will this be the year that South Dakota State (30-13, 16-4) breaks Oral Roberts' (25-18, 14-6) stranglehold on the conference? The conference tournament is in South Dakota this year, but the Jackrabbits travel to Tulsa this week for the regular-season set against the Golden Eagles.

SWAC: Southern (26-18, 16-8) and Alcorn State (22-23, 19-4) won the regular-season division titles. An Eastern Division team hasn't won the tournament championship (and conference automatic bid) since Jackson State in 2000.

West Coast: There's no conference tournament in the WCC, but the title will be determined on the final weekend when San Francisco (25-22, 11-4) visits Gonzaga (26-13-1, 9-3). The other teams in the conference all have at least six losses.

A look at the field of 64:

Jeremy Mills is a researcher for ESPN and is a contributor to ESPN.com's college baseball coverage.

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