Duke (4) and Virginia (5) have sprung into the nation's top five teams, replacing Syracuse and Kansas respectively, but somehow neither team is currently a one-seed in the NCAA Tournament.

In the Associated Press' 18th week of the top 25 in men's basketball, Syracuse (7) and Kansas (8) each fell three spots, giving way to Duke and Virginia joining Florida (1), Wichita State (2) and Arizona (3) in the top five. Still, according to ESPN's Joe Lundardi, Kansas has now surpassed Syracuse for the one-seed in the East division of the NCAA Tournament.

As it stands, Wichita State is the top team in the Midwest, Arizona in the West and Florida in the South. Wisconsin, Duke, Syracuse and Villanova make up the two-seeds while Virginia is a three-seed.

With one week left to play in the regular season, the NCAA Tournament bracket is very close to being set, so the only way to shake things up would be a flurry of upsets.

UConn (19) tied Virginia for the largest leap in the rankings with seven places after beating South Florida and Cincinnati (15) this week. Oklahoma (23) joined UConn in re-entering the rankings, replacing Ohio State and Texas.

Iowa's (24) win over Purdue likely saved the team from falling out of the top 25 as they fell four places thanks to losses to Minnesota and Indiana.

The largest fall belonged to Kentucky, who fell eight spots after losing to both Arkansas and South Carolina. They finish their season against Alabama and Florida.

Saint Louis (17) was another two-loss team this weak and fell seven places after dropping contests against Duquesne and VCU.

On the other hand, UNC (14) continued their late-season push and rose five places, remaining a five-seed in the South.

As the season comes to a close, the tournament's one-seeds are all but set. Florida and Wichita State figure to have theirs locked up, but Arizona and Kansas are going to need to avoid upsets to protect theirs.