Of the 15 players named to the three Associated Press All-America teams last season, only two return: Notre Dame's Bonzie Colson and Wisconsin's Ethan Happ. Throw in an NBA draft lottery that saw 11 college freshmen and two college sophomores selected, and a lot of talent left college basketball since the season ended in April.
With that said, several programs that lost high-end players from a season ago are back among the national title contenders -- provided they can find successors for the departing stars.
So who are the key replacements who could shape the college basketball season?
Kansas Jayhawks
Gone: Frank Mason
Last season's Wooden Award winner, Mason went from an under-recruited, Towson-bound high schooler to an unguardable playmaker at the college level. Jayhawks coach Bill Self will bid farewell to Mason's 20.9 points and 5.2 assists per game -- and more important, his toughness, leadership and clutch performances late in games. Devonte' Graham probably will take over the majority of point guard duties after playing alongside Mason in a two-point-guard backcourt for the past couple of seasons. The key member in this backcourt will be Mississippi State transfer Malik Newman, who is now eligible after sitting out last season. Newman is a former five-star prospect who was considered the best guard in the country in the class of 2015. He struggled during his lone season in Starkville, Mississippi, though, shooting below 40 percent. With less pressure on his shoulders in Kansas and the ballhandling responsibilities going to Graham, Newman can focus on what he does best: scoring the ball. Self will need it.
Villanova Wildcats
Gone: Josh Hart
Expect something of a different look from Jay Wright and Villanova after the departure of Hart -- along with fellow seniors Kris Jenkins and Darryl Reynolds. The Wildcats might not go with four guards on the court as often, and they have more size and frontcourt talent than they've had in a long time. Starting point guard Jalen Brunson will take on a bigger role offensively, but he's already established as one of the best at his position in America. Wright needs someone to replace Hart's 18.7 points and versatile offensive game. Could the answer be Donte DiVincenzo? The Delaware native had his moments last season, including averaging 18.0 points in the NCAA tournament and scoring 25 points in a Big East tournament win over St. John's. He has plenty of confidence on the offensive end and is strong enough to play as the 3-man in Villanova's system. Incoming freshman Jermaine Samuels will make an impact early, but DiVincenzo could end up leading the team in scoring.
UCLA Bruins
Gone: Lonzo Ball
Well, Ball is gone -- and so is nearly everyone else from UCLA's 31-win campaign a season ago. But Ball is the one who elevated everyone on the roster and was the key catalyst in UCLA having the second-most efficient offense in college basketball. Ball was such a good passer and so unique a player; there's no one else like him to step in and replicate what he did. Steve Alford does have two aggressive playmakers ready to lead the offense, though: returnee Aaron Holiday and freshman Jaylen Hands. Holiday had a better season as a sophomore despite a decrease in minutes from his freshman season. He's a tough point guard who can get into the lane with ease but also made better than 40 percent of his 3-pointers. Hands is a tremendous athlete who excels in the open floor and will look to keep UCLA playing fast. The McDonald's All-American has good size and will produce highlight-reel plays. Between Holiday and Hands, Alford has a dangerous backcourt ready to roll.
Kentucky Wildcats
Gone: De'Aaron Fox, Malik Monk
John Calipari loses his top seven scorers from last season, led by the elite backcourt of Fox and Monk. Fox established himself as a terrific two-way point guard and Monk was perhaps the most dangerous scorer in the country when he got going. Kentucky brings in more than enough talent to fill in the gaps, but there are questions. Point guard probably will go to incoming five-star recruit Quade Green, whose floor game improved considerably as his high school career progressed. He has terrific vision and changes speeds effectively. Canada native Shai Gilgeous-Alexander is earning preseason hype due to his ability to play on or off the ball. He has very good size and can score in a variety of ways. Most are expecting Hamidou Diallo to shoulder much of the offensive load after sitting out the second semester in Lexington last season. Diallo is an explosive athlete who makes plays in transition. The biggest question for Kentucky heading into the season will be shooting and spacing; who will replace Monk's perimeter prowess?
Purdue Boilermakers
Gone: Caleb Swanigan
Purdue brings back four starters and five of its top six from a 27-win team -- yet the Boilermakers are just a borderline top-25 team heading into the season. The reason? That one player gone was the best big man in college basketball a year ago. Swanigan was a threat to go for 20 points and 10 rebounds every night, while also dishing out assists and making nearly 45 percent of his 3-point attempts. Fortunately for Matt Painter, he has a proven 7-footer ready to take on a bigger role. Isaac Haas, a 7-foot-2 center, has been productive and efficient in his minutes the past three seasons. As a senior, though, Haas will need to become a go-to weapon on the interior -- for more than 20 minutes per game. Haas averaged 19.5 minutes last season and hit the 20-minute mark just three times in Purdue's final 16 games. It wasn't always easy to play Haas and Swanigan together, but now's the chance for Haas to prove himself. His per/40 numbers are around 25 points and 10 rebounds; no one is expecting that, but a consistent campaign from Haas will go a long way toward keeping the Boilermakers in the top 25.
Duke Blue Devils
Gone: Luke Kennard, Jayson Tatum
Seven of Duke's top eight players from last season have moved on -- yet the Blue Devils are the favorite to open the 2017-18 campaign as the No. 1 team in the country. There's an elite recruiting class entering the fold, along with the return of Grayson Allen. There won't be a lack of scoring in the Blue Devils' lineup, but Mike Krzyzewski will have to figure out his perimeter group, primarily the point guard position, early in the season. Allen and Kennard were the top assist-makers on last season's team, but Krzyzewski will prefer to have Allen to stay off the ball this season. That means incoming freshman Trevon Duval, the No. 1 point guard in the 2017 class, will have to run the offense. He's an elite playmaker with the ball in his hands but has to show he can get all the other scorers involved and make good decisions in the half-court. That would enable Allen, who averaged 21.6 points in 2015-16, to focus on scoring. Throw in volume scorer Gary Trent Jr., another incoming five-star prospect, and Duke will have a potent perimeter group. It starts with Duval, though. Replacing the scoring of Kennard and Tatum will be the easy part.