Power Rankings: Now we wait to assess impact of Zion Williamson injury on Duke

Coach K: Zion has a 'mild knee sprain' (1:04)

Mike Krzyzewski doesn't know the timetable after Zion Williamson's knee injury and laments losing another big player early in a Duke loss. (1:04)

The landscape of the 2018-19 college basketball season might have shifted on Wednesday night ... but we don't know that just yet.

Duke lost by 16 points at home to North Carolina, but the biggest storyline coming out of Durham is the status of Zion Williamson. The Wooden Award favorite left the game after just 36 seconds after he slipped, blew out his shoe and fell awkwardly, holding his knee. Duke coach Mike Krzyzewski described it as a mild right knee sprain, but we don't know the potential timeline for his return.

If Williamson is out for a significant amount of time, whether that's the rest of the season, the rest of the regular season or something else, Duke's status as the best team in college basketball takes a hit. For now, the Blue Devils' résumé is still vastly superior to everyone else's in college basketball -- and with Williamson, they're still the most impressive team in college basketball.

But we'll wait and see.

Williamson's injury also overshadowed an extremely impressive performance from North Carolina. The Tar Heels shot just 2-for-20 from 3-point range, turned the ball over 16 times -- and still never trailed in dominating at Cameron Indoor Stadium. Luke Maye might have been at a disadvantage had Williamson played, but he finished with 30 points and 15 rebounds with Williamson sidelined. Wednesday's win also gave North Carolina another elite marquee win, adding to its victory over Gonzaga earlier this season.

It also sets up a three-way race for the ACC regular-season title. North Carolina, Duke and Virginia are all tied at 11-2, with the Tar Heels beating Duke, Virginia beating North Carolina and Duke beating Virginia twice. The only game remaining between the three teams is Duke at North Carolina on March 9.

But for now, those narratives take a back seat. All eyes in college basketball are on Williamson's knee diagnosis.

Monday: Put Kentucky in the top tier now, please

Is it time to expand the elite group to five teams and include Kentucky?

The temptation is there after the Wildcats obliterated Tennessee in the second half of Saturday's 17-point win in Lexington, but remember, we've gone down this path with the Wildcats a few times this season.

Obviously, we did it at the start of the season before they lost by 34 to Duke. Then we did it after they handled North Carolina in Chicago and won at Louisville by 13 -- but then lost at Alabama by two points. The bandwagon got full again after the 10-game win streak in January and February, prior to the home defeat to LSU.

And now, we try it again after a win over Tennessee.

Take the entire season into account, though, and it's pretty clear that Kentucky is among the five best teams in the country right now. The Wildcats have lost three games since Nov. 6 by a combined five points. They're No. 5 at KenPom and No. 6 in the NET, BPI and Sagarin rankings. They've beaten Tennessee, North Carolina, Kansas and Louisville, and they have eight Quadrant 1 wins -- third-most of anyone in the country.

The Wildcats have an elite defense, one that has improved considerably since Ashton Hagans took over the starting point guard duties. They are currently ranked No. 8 in adjusted defensive efficiency at KenPom, but if you take into account just the games since Hagans moved into the starting lineup, BartTorvik.com has the Wildcats with the No. 4-ranked defense.

Offensively, they still have some issues shooting the ball, making 10 or more 3-pointers just three times all season, but they're one of the best offensive rebounding teams in the country and get to the free throw line at a high rate. More importantly, they finally found a consistent go-to guy: PJ Washington. Washington has played as well as anyone in the country over the past month, making a push for All-American honors. He has scored 20 or more points in seven of his past eight games.

We're not saying John Calipari has a perfect team or is even a Final Four favorite, but the Wildcats have steadily improved since the opening night embarrassment and are hitting their stride according to the typical Calipari timeline.

The Tennessee rematch on March 2 in Knoxville is going to be a true litmus test for the young Wildcats away from home -- and will go a long way toward determining the SEC regular-season champion -- but right now, Kentucky has a strong case for being a solidly top-five team.

1. Duke Blue Devils (23-3)
Previous ranking: 1
This week: Lost to North Carolina 88-72 on Wednesday, at Syracuse (Saturday)

Without knowing the severity of Williamson's injury, it's hard to knock Duke out of the No. 1 spot from a body-of-work standpoint. But Wednesday's outing wasn't pretty. Duke missed 31 3-pointers -- the second time this season they've missed 30-plus 3s. They allowed 62 points in the paint -- the first time since 2014-15 they yielded 60-plus paint points. And the Blue Devils' offense was almost exclusively reliant on Cam Reddish and RJ Barrett. Syracuse had Duke's number once already this season; can the Orange finish the sweep at the Carrier Dome on Saturday?

2. Virginia Cavaliers (23-2)
Previous ranking: 2
This week: Beat Virginia Tech 64-58 on Monday, at Louisville (Saturday)

Virginia has only the two losses to Duke on its ledger, but the Cavaliers have looked off the pace a little bit in recent weeks. They went to Virginia Tech and beat the Hokies on Monday, but turnovers were once again an issue. It was the fourth time in the past six games that Virginia turned it over on at least 20 percent of its possessions -- a number the Cavaliers hit just four times all of last season. Tony Bennett will hope to see his team tighten up its passing and decision-making moving forward.

3. Tennessee Volunteers (24-2)
Previous ranking: 3
This week: Beat Vanderbilt 58-46 on Tuesday, at LSU (Saturday)

Tennessee bounced back from its first loss in two months with a win on Tuesday, but the Volunteers had their worst offensive performance of the season against a team that's winless in the SEC. Tennessee has shot just 13-for-46 from 3-point range in the past two games, and the Volunteers rely on that perimeter balance to open the lane for Grant Williams & Co. up front. Tennessee did have its best defensive performance of the SEC campaign on Tuesday, though.

4. Gonzaga Bulldogs (26-2)
Previous ranking: 4
This week: Beat Pepperdine 92-64 on Thursday, vs. BYU (Saturday)

Especially with Killian Tillie sidelined, there's a good chance freshman Filip Petrusev will have to play a role for Gonzaga in the NCAA tournament -- and when given the opportunities, Petrusev has delivered. He had eight points off the bench on Thursday. Petrusev has now played double-figure minutes four times in West Coast Conference play, and averaged 10.8 points and 3.8 rebounds.

5. Kentucky Wildcats (22-4)
Previous ranking: 5
This week: Beat Missouri 66-58 on Tuesday, vs. Auburn (Saturday)

Kentucky won at Missouri on Tuesday, but John Calipari will have a big concern moving forward: Senior forward Reid Travis left the game in the second half, and the school announced that he has a sprained right knee. We will have to wait to see the extent of the injury, but if Travis is out for an extended period, backups EJ Montgomery and Nick Richards will need to play bigger roles. Travis gives the Wildcats experience and toughness down low.

6. North Carolina Tar Heels (22-5)
Previous ranking: 8
This week: Beat Duke 88-72 on Wednesday, vs. Florida State (Saturday)

Wednesday's game was a thoroughly dominant performance by the Tar Heels. Maye, Cameron Johnson and Garrison Brooks simply overwhelmed Duke inside, combining for 70 points and 30 rebounds. North Carolina scored 62 points in the paint and forced Duke into 39 3-point attempts. The Tar Heels now own wins over Duke and Gonzaga, perhaps the best combination of wins in the country outside of Duke's two victories over Virginia.

7. Michigan Wolverines (24-3)
Previous ranking: 6
This week: Beat Minnesota 69-60 on Thursday, vs. Michigan State (Sunday)

The Wolverines went to Minnesota and handled the Golden Gophers -- with a 36-point advantage from behind the 3-point line. This sets up a showdown on Sunday against Michigan State for first place in the Big Ten. The Wolverines have the edge going into this one because the game is being played in Ann Arbor and the Spartans will be without Nick Ward down low. If Zavier Simpson can stifle Cassius Winston, Michigan gets a win.

8. Houston Cougars (25-1)
Previous ranking: 7
This week: vs. South Florida (Saturday)

Houston caught fire in the second half against Tulane -- including a 35-5 run that spanned just about 10 minutes and featured nine Houston 3-pointers -- for the Cougars' 25th win of the season. Armoni Brooks and Corey Davis Jr. have been the stars for Kelvin Sampson all season, and Sunday was no different. The two combined for 14 3-pointers and 50 points. Houston's résumé continues to improve, and the December win over LSU looks better and better.

9. Michigan State Spartans (22-5)
Previous ranking: 9
This week: Beat Rutgers 71-60 on Wednesday, at Michigan (Sunday)

Another slow start, but another double-digit win for Michigan State, as the Spartans scored 46 points in the second half to erase a halftime deficit. Without Nick Ward, coach Tom Izzo needed some role players to step up, and Xavier Tillman responded. Tillman had 19 points and 10 rebounds after being inserted into the starting lineup. Michigan State will need more of the same with a trip to Ann Arbor looming on Sunday.

10. Kansas Jayhawks (20-6)
Previous ranking: 11
This week: at Texas Tech (Saturday)

Well, look at the Big 12 standings now. Kansas is just a half-game back of Kansas State, tied with Texas Tech for second place. Can the Jayhawks win the Big 12 yet again? They have a week off before heading to Lubbock for their toughest remaining game on the schedule: at Texas Tech. The Red Raiders have won four in a row, but Kansas blew them out by 16 earlier this month in Lawrence.

11. Marquette Golden Eagles (22-4)
Previous ranking:
This week: Beat Butler 79-69 on Wednesday, at Providence (Saturday)

Things are starting to open up a little bit for Marquette in the Big East standings. With Villanova losing three of its past four games, the Golden Eagles now have a one-game lead by themselves at the top of the league. Markus Howard's 28 points on Wednesday will get the headlines, but Theo John going for 15 points, 11 rebounds and 3 blocks -- while committing just one foul in 32 minutes -- might have been more important.

12. Purdue Boilermakers (19-7)
Previous ranking: 13
This week: Beat Indiana 48-46 on Tuesday, at Nebraska (Saturday)

Purdue isn't going to win too many games with Carsen Edwards shooting 4-for-24 from the field, but the Boilermakers got a tip-in from Matt Haarms with 3.2 seconds left to beat Indiana in Bloomington. They are now in a dead heat with Michigan and Michigan State for first place in the Big Ten -- and they have the easiest remaining schedule of the three teams.

13. Texas Tech Red Raiders (21-5)
Previous ranking:
This week: vs. Kansas (Saturday)

Texas Tech replaces Iowa State after the Cyclones lost to Baylor at home on Tuesday. Chris Beard and the Red Raiders are right in the thick of the Big 12 hunt after winning four in a row -- and they have a real opportunity this weekend, when Kansas comes to Lubbock. After a couple slip-ups in mid-January, Tech is back playing defense at an elite level. Its past four opponents have scored a combined 0.80 points per possession.

14. Nevada Wolf Pack (24-2)
Previous ranking: 10
This week: Lost to San Diego State 65-57 on Wednesday, vs. Fresno State (Saturday)

Nevada suffered just its second defeat of the season on Wednesday, looking out of sorts for most of the loss at San Diego State. Jordan Caroline had one of his worst games of the season, finishing with eight points before fouling out -- and the Wolf Pack too often ended up forcing contested shots. The loss snapped a 10-game winning streak, and they now have two tough games coming up versus Fresno State this weekend and at Utah State next weekend.

15. LSU Tigers (21-5)
Previous ranking: 14
This week: Lost to Florida 82-77 (OT) on Wednesday, vs. Tennessee (Saturday)

LSU might have been caught looking ahead to Saturday a little bit on Wednesday, as the Tigers fell at home in overtime to Florida. The two biggest reasons for their recent hot streak were Tremont Waters and Naz Reid -- and those two went 8-for-24 on Wednesday. All that said, LSU still has a chance to force a tie at the top of the SEC standings with Tennessee coming to Baton Rouge this weekend.

16. Wisconsin Badgers (18-8)
Previous ranking:
This week: Beat Illinois 64-58 on Monday, at Northwestern (Saturday)

Wisconsin holds off Florida State to earn the final spot in the rankings after Louisville lost its fourth game in its last six. The Badgers snapped a two-game losing streak with a win over Illinois on Monday, and they should be favored in each of their final five games. Greg Gard has to solve the late-game Ethan Happ issue, though. Happ hasn't made a free throw since Feb. 6. He's 0-for-10 from the stripe in his last three games.

Dropped out: Louisville (No. 15)