Before this season began, many pundits touted the college game’s overall depth of field, saying that any one of 10 or even 15 teams had a shot at the national title.

Three months later, that number has been reduced considerably as strengths have been revealed and weaknesses exposed. Now that Boston College has been evicted from the ranks of the undefeated and could well fall out of the top 10, this season’s legitimate contenders for a Final Four date in St. Louis can all be found at or near the top of the polls.

Given what we’ve seen so far, it’s no stretch to suggest that the Final Four lineup will include:

ILLINOIS The Illini have gone unbeaten through a minefield of tough Big Ten opponents, as well as non-conference foes like Gonzaga and Cincinnati. Critics may deride their lack of a conventional, back-to-the-basket big man, but coach Bruce Weber has deftly mixed and matched the undersized Roger Powell, slender James Augustine, and journeyman Jack Ingram into a formidable, if not dominant, rotation.

The key to this juggernaut is the nation’s best backcourt. Dee Brown and Deron Williams are the most versatile duo in the country, either one capable of playing the point or the shooting guard position. Third guard Luther Head, unheralded before this season, is having his best year, leading the Illini in scoring and the Big Ten in 3-point shooting.

Illinois scores a lot of points, but it is also remarkably stingy on defense, smothering opponents with a man-to-man scheme that Weber learned from his days as an assistant to Gene Keady at Purdue.

KANSAS The Jayhawks survived a midseason injury to All-American forward Wayne Simien – beating, among others, Georgia Tech at home and Kentucky on the road without him – and save for one puzzling loss at Villanova, they have played as well as coach Bill Self could have hoped.

Simien has led the Jayhawks in scoring in six of the eight games since his return, but this team proved during the big man’s absence that it doesn’t revolve around just one man. Kansas can rely on several experienced players to carry the team. Senior guard Aaron Miles is one of the nation’s most exciting playmakers, and his emergence this season as a real shooting threat (57% from 3-point range) has made him all the more dangerous.

Senior Keith Langford and sophomore J.R. Giddens give the Jayhawks a pair of rangy, athletic scorers who can get baskets at critical times. Both have the ability to slash to the rim, making them difficult to defend and easy to foul. Unfortunately, neither one is making even 70% of his free throws.

The injury to Simien also allowed a handful of talented freshmen frontcourt players – Alex Galindo, Sasha Kaun, C.J. Giles, and Darnell Jackson – to earn some minutes they wouldn’t have gotten otherwise, so this is a deep team for the stretch run.

NORTH CAROLINA Coach Roy Williams has the best collection of athletes in the country, and he’s getting the most out of them with his up-tempo philosophy. The Tar Heels lead the nation in scoring and are third in field goal percentage, a testament to the effectiveness of their transition game, which results in easy layups, uncontested 3-pointers, and early double-digit leads.

Rashad McCants, Raymond Felton, Jawad Williams, and Sean May deservedly soak up most of the attention, but as we’ve seen before, it’s the emergence of an unknown talent that could give this team the extra push it needs to storm St. Louis.

Freshman Marvin Williams, a 6-foot-9, 240-pound “freak of nature,” as Mc-Cants calls him, has more than solved North Carolina’s frontcourt depth problems. In a rout of N.C. State last Thursday, Williams scored 20 points on a flurry of 3-pointers, dunks, and post moves, then came back to drop 13 points and eight rebounds in a win over Florida State.

DUKE With huge wins over Michigan State and Oklahoma, it has become apparent that the Blue Devils are capable of working around their serious lack of depth for a deep Tournament run. Coach Mike Krzyzewski has already won a national title with a rotation of just seven men, and luckily, the current nucleus has the talent and experience to equal the feat.

Forward Sheldon Williams, averaging 16.8 points and 11.2 rebounds, has a chance to become the first Duke player in Krzyzewski’s tenure to average a double-double. Think about how many great players have come through the program and you’ll realize how impressive that achievement would be. Guard J.J. Redick is the best shooter in the country, and Daniel Ewing is always reliable as a scorer and playmaker.

The key to Duke’s title bid, though, might be Shavlik Randolph, the junior post man whose return from a bout of mono provided some help in the frontcourt. If Randolph can recover his pre-illness shape, Duke might have just enough man power to last through March.

OTHERS WITH A SHOT In no certain order, Louisville, Kentucky, Syracuse, and Wake Forest all have a chance to replace one of the teams mentioned above.

Louisville coach Rick Pitino has done a masterful job of steering his team around personnel defections and injuries. Before a 77-73 win at Alabama-Birmingham on Saturday, the Cardinals had won eight straight games by an average of nearly 30 points.

Kentucky coach Tubby Smith has skillfully blended newcomers into a strong foundation that includes forward Chuck Hayes and scoring guard Kelenna Azubuike. The Wildcats, undefeated in SEC play, have a big upside because those freshmen, notably point guard Rajon Rondo and center Randolph Morris, improve with every game. And three sophomores, forwards Bobby Perry and Sheray Thomas and center Shagari Alleyne, are also becoming regular contributors.

This is a deep team that plays tough man-to-man defense. But can underclassmen carry a program all the way to the promised land?

Syracuse boasts more than enough talent – notably All-American forward Hakim Warrick and junior sharpshooter Gerry McNamara – to win coach Jim Boeheim’s second championship in three years. A loss to UConn on Monday night, though, betrayed the team’s problems with fouling too much and closing out games.

Wake Forest, a popular preseason no. 1 pick, forces a load of turnovers and can shoot the lights out from the perimeter, which Duke learned the hard way last week. The Deacons always have a great chance to win when sophomore point guard Chris Paul takes over a game, which he’s been doing with increasing regularity.

FAVORITE Roy Williams’s stable of thoroughbreds at UNC look poised to keep running all the way to the finish line. Outside of the scoring threats and freshmen depth, Jackie Manuel is a defensive marvel who can shut down big guards and small forwards alike. If they can keep the engine running at full power, the Tar Heels should snag Williams his long-overdue national championship.

Mr. Dortch is the editor-in-chief of the Blue Ribbon College Basketball Yearbook.