A spotlight has been on Marvin Bagley III since he reclassified to enter Duke — and thus enter the NBA draft — a year early. (Gerry Broome/Associated Press)

Mike Krzyzewski, who will begin his 38th season as Duke’s basketball coach Friday, said this earlier this week: “This will be the youngest team we’ve had since the [Johnny] Dawkins-[Mark] Alarie-[Jay] Bilas-[David] Henderson group back in 1982. Of course, this group’s expectations are a little bit different.”

No kidding. Back then, when Krzyzewski had the top-rated recruiting class in the country, no one expected much from his team that season. They were right. Duke finished 11-17, including a home loss to Wagner and a 109-66 defeat to Virginia in the ACC tournament.

That was what happened when you started four freshmen.

Krzyzewski again has the top-rated recruiting class in the country and will start four freshmen this season. His team is No. 1 in the Associated Press and coaches' preseason polls. Michigan State is No. 2 in large part because Miles Bridges decided to return to college for a second year. Bridges is the consensus preseason national player of the year, at least in part because he has that one season under his belt.

That’s what college basketball has become. Once upon a time, a team starting four freshmen — any four freshmen — was considered to be at least a year away from seriously contending for anything. The group that Krzyzewski brought in for his third season improved steadily, finally peaking when all four were seniors and Duke went 37-3, won the ACC title and lost to Louisville in the national championship game.

This year’s group will be long gone by the time the 2020-21 season — when they would be seniors — rolls around. In fact, it’s likely that they all will be gone by next spring, unless one of them surprises and follows Bridges’s example.

“You can’t coach with next season in mind anymore,” Krzyzewski said. “You have to coach this team this year because in all likelihood you won’t be coaching your best players a year from now.”

Not if you’re Krzyzewski, Arizona’s Sean Miller, Kansas’s Bill Self or Kentucky’s John Calipari. All face the challenge of replacing one-and-dones on an annual basis. And, almost without fail, they find themselves ranked in the top five in the next year’s preseason poll. This year is no different. Arizona, Kansas and Kentucky are Nos. 3 through 5, in slightly different order, in the initial polls.

Only when you get to Villanova and Wichita State at Nos. 6 and 7 in the AP rankings do you start to see teams built more on experience than on one-and-dones — Michigan State and Tom Izzo being the notable exceptions.

“We’ve had a couple,” Izzo said, referring to one-and-dones. “I certainly thought Bridges would be one when we recruited him. But he’s a different kind of kid.”

What makes college basketball still worth watching is this: The November hype is almost always about the one-and-dones. And yet by March, experience starts to matter. South Carolina wasn’t even ranked in last season’s preseason poll, and yet it took down Duke — which had four underclassmen turn pro, three taken in the first round of the NBA draft — en route to the Final Four.

Kentucky also produced three first-round picks in that draft. It didn’t make the Final Four. Oregon, which had no one taken in the first round, did make it to Phoenix. In fact, none of last year’s preseason top four made it to the top four that mattered: Duke lost in the round of 32, Kentucky in the round of eight, Kansas in the round of eight (to Oregon) and defending champion Villanova in the round of 32. Only Villanova was ranked that high without a player considered a lock one-and-done on its team.

“A lot of those preseason rankings are about the one-and-done guys,” Izzo said. “The kids get so much preseason hype, and they have played more basketball than kids used to coming in to college in the old days. But the whole thing with talking about where they’re going in the draft before they play a college game is over the top.”

When Marvin Bagley III announced in August that he was reclassifying to go to college this year instead of next and would attend Duke, every story about his commitment led with some form of “Marvin Bagley III, who is considered the likely No. 1 pick in next June’s NBA draft . . .”

Bagley didn’t reclassify so he could be a Duke student. He reclassified to get into the draft a year sooner.

Duke and Michigan State will play in Chicago on Tuesday as part of the annual doubleheader that also includes Kansas and Kentucky. The four blue bloods gather in an NBA arena the first Tuesday of the season and rotate opponents. It is the classic TV showcase, an ESPN extravaganza filled with as much hype as the planet can stand.

Four years ago, Kansas had Andrew Wiggins, Kentucky had Julius Randle and Duke had Jabari Parker — all hyped-beyond-belief one-and-dones. At the end of the evening, one noted ESPN pundit declared the night “the greatest night in the history of regular season college basketball.”

Somewhere, Kareem Abdul-Jabbar and Elvin Hayes cringed. The games themselves were fairly ordinary, but it was all about the freshmen. In March 2014, Randle was part of a Kentucky team that made the national title game as a No. 8 seed after struggling much of the season. Wiggins’s Kansas team lost to Stanford in the second round. Parker’s Duke team didn’t get that far, losing to Mercer in the first round.

If you had told the TV geniuses on the “greatest night in the history of regular season college basketball” that Parker would never be part of a team that won an NCAA tournament game, you would have been laughed out of the building.

“That team was built on seniors, five guys who were 21, 22, 23 years old who had been to war with one another,” Krzyzewski said of that Mercer team. “We had more talent, but it was young talent, still-learning talent. That’s why in March teams with experience can win even if they don’t have lottery picks on the roster.”

That's why since the one-and-done became part of college basketball in 2008, teams such as Butler (twice), VCU, West Virginia and Wisconsin (twice) have all reached the Final Four without a one-and-done in sight. Last year, it was Oregon and South Carolina. Gonzaga had a player who turned out to be a one-and-done, Zach Collins, but he didn't even start for most of the season. Title winner North Carolina was built around juniors and seniors; reserve Tony Bradley was the Tar Heels' first one-and-done since 2007,.

“It isn’t as if we don’t try to recruit one-and-dones,” said Notre Dame Coach Mike Brey, who has taken his team to the Elite Eight twice in the past three seasons. “Realistically, we probably aren’t going to get them because there are other places that guys look at as one-and-done schools. So we go after kids who I hope will have that ‘junior light’ go on.”

His point guard this season, senior Matt Farrell, is a perfect example of the “junior light.” Farrell barely played most of his sophomore season, then became a star a year ago.

So, too, is national player of the year candidate Bonzie Colson, who averaged 5.6 points and 2.7 rebounds as a freshman, improved as a sophomore and then erupted as a junior, averaging better than 17 points and 10 rebounds. Notre Dame, led by Colson and Farrell, is ranked 14th in the preseason. No one will want to play the Irish come March.

So sit back the next few weeks and listen to all the screeching about the “Diaper Dandies,” the phrase Dick Vitale invented years ago when it still meant that freshmen weren’t quite ready to lead teams to the promised land.

Then look around in March. The one-and-dones will be there, but so will teams such as Notre Dame, Villanova, Wichita State and Michigan State — the Spartans led by Bridges, the wise old man of college basketball.

For more by John Feinstein, visit washingtonpost.com/feinstein.

Correction: Due to an editing error, an earlier version of this story incorrectly said that North Carolina had not had a freshman player enter the NBA draft since 2007.