One of the most polarizing leaders in American history made headlines recently, the nature of which is so significant that historians may one day consider the past week to be the beginning of the end of his reign. I’m talking, of course, about Duke men’s basketball coach Mike Krzyzewski.

Last Thursday, news broke that the Blue Devils would cancel their trip to the Dominican Republic because Coach K needed a knee replacement, a procedure that reportedly went as well as expected. In and of itself, a knee replacement for a 70-year-old is not noteworthy. It’s a routine operation with a relatively quick recovery period that should help Krzyzewski get back to his athletic prime of jumping three inches off the ground to celebrate winning an Olympic gold medal. But when you consider that this was Coach K’s second surgery in 2017 and sixth surgery within the past year and a half, suddenly the unthinkable starts to feel imminent: Maybe there really will come a day when he is no longer Duke’s head coach.

Anyone who has a personal relationship with Krzyzewski will tell you that the coach has no plans of hanging up his whistle soon, which makes sense given that all of these surgeries are surely his attempt to transform into a cyborg and live forever. History suggests that a different reality is coming, however, as college basketball coaches have rarely remained on the bench into their 70s. John Wooden was 64 when he retired. Henry Iba was 65. Dean Smith coached his last game at 66, Bob Knight at 67, and Jim Calhoun at 69. Even the famous names who have stuck with the job into their 70s—Phog Allen, Ray Meyer, Eddie Sutton, Lou Henson, Jerry Tarkanian, Steve Fisher, and Lefty Driesell—generally haven’t lasted long once they got there, as all those listed except Henson retired before their 73rd birthday. (And Henson retired 12 days after he turned 73.) Adolph Rupp retired when he was 70 only because of a Kentucky mandate that forced all state employees to retire at that age, so maybe he could have lasted for another decade. Or, considering that he died shortly after turning 76, maybe not. The high-age watermark for legendary Division I college basketball coaches belongs to John Chaney, who retired at 74 a year after instructing his players to injure their opponents, and Lute Olson, who was forced into retirement at 74 after finding out he’d had a previously undiagnosed stroke. (For what it’s worth, Rollie Massimino is 82 and still coaching at an NAIA school, Keiser University. But his Division I career ended when Cleveland State fired him in 2003 at the age of 68.)

This is what Coach K is up against. He’s proved himself to be a coaching anomaly in virtually every other respect, so perhaps staying on the Duke sidelines for another 15 years isn’t as improbable as it seems. It should also be noted that the only thing getting 72-year-old Syracuse head coach Jim Boeheim out of bed in the morning is the hope that Krzyzewski will retire in short order so Boeheim can make a run at becoming college basketball’s all-time winningest coach (he has 1,004 career wins to Krzyzewski’s 1,071), a scenario that Coach K will never let happen. Still, six surgeries in 16 months is far from insignificant, and for a man who could retire today as the greatest coach the sport has ever known and who has enough money to financially support his grandchildren for their entire lives, it’s easy to wonder what’s keeping him going. (Answer: “the next one.”) Thus, while Coach K says he’s Duke’s man for the foreseeable future, the odds say that a new Duke coach will be named within the next five years.

The rub is that nobody seems to have any idea who Krzyzewski’s successor will be, despite rampant speculation over the years. And as the most important Duke news of the week underscored, answering that question is becoming increasingly complicated the closer we get to that inevitable day.

Marvin Bagley III’s announcement on Monday that he will skip his senior year of high school and enroll at Duke sent shock waves through the college basketball world. The Blue Devils immediately became heavy national title favorites, and for good reason: The 6-foot-11 220-pounder is being hailed as a generational talent and drawing comparisons to Anthony Davis, who in 2011-12 at Kentucky produced the greatest freshman season in the history of the sport. A player of that caliber picking a school over 2,000 miles from his home state of Arizona just two weeks before classes start is a massive coup for the Blue Devils. With three other top-10 recruits (Wendell Carter, Trevon Duval, and Gary Trent Jr.) already signed, Duke now enters the 2017-18 season with a potential starting five that will make your head spin.

It almost seems too perfect that Bagley announced his decision one day after Coach K had his knee-replacement surgery and reminded the world of his mortality. While nobody within the program seems keen on discussing what will happen once the Krzyzewski era ends, we now at least have a sense of what Duke will look like for the remainder of Coach K’s career. That comes in the form of guys like Bagley, the crown jewel of this new era of Duke basketball and a symbol that Coach K has unequivocally gone all in on playing the one-and-done game.

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Before I go further, I should make clear that I’m not here to condemn Krzyzewski or any other coach for wanting to ride the one-and-done carousel. The ultimate goal in sports recruiting is to attract the most talented players, and every coach in America would gladly welcome one-and-done guys if they had the chance. In the 11 seasons since the NBA changed its eligibility requirement so that a player couldn’t be drafted until he was “at least one year removed from the graduation of his high school class,” only two teams have won national titles using a one-and-done approach (Kentucky in 2011-12 and Duke in 2014-15). There’s no point in getting worked up over this notion that the likes of Duke and Kentucky are ruining the competitive balance of college basketball.

I just find it fascinating how Krzyzewski arrived at this point. Over the course of almost four decades he’s built the most distinct and consistently excellent program in America, and he’s done so largely by using a recruiting strategy to find guys who, regardless of their talent level, fit into the Duke culture. Coach K’s emphasis on culture-building has been unmistakable, to the point that whether you love or hate the Blue Devils, I can say the words “Duke basketball” and you will feel something. Vivid images will appear in your mind, certain adjectives will make their way to the tip of your tongue, and your body language will reveal which side you fall on. That’s a testament to all that Krzyzewski has built.

It’s also exactly why it’s so jarring to see Krzyzewski embrace such a massive cultural shift in the final act of his career. I don’t know if this change was brought on by John Calipari becoming college basketball’s darling with his one-and-done philosophy at Kentucky, by super-recruiter Jeff Capel’s addition to the Duke staff in 2011, or by some combination of both factors. I just know that after decades of Duke basketball standing for chemistry and toughness, Coach K’s recent teams have been remarkably inconsistent messes that don’t mesh and can’t guard ball screens for shit.

The one glaring exception is the 2014-15 team that overcame midseason struggles, got hot at the right time, and delivered Krzyzewski his fifth national title. In doing so, that group validated the program’s one-and-done experiment after teams led by Kyrie Irving, Austin Rivers, and Jabari Parker had previously crashed and burned in the NCAA tournament. Five years earlier, Coach K captured the 2009-10 title with Brian Zoubek as his starting center, zero NBA lottery picks, and only one first-rounder (Nolan Smith) in his starting lineup. Now he had won a championship by trotting out three one-and-dones (Jahlil Okafor, Justise Winslow, and Tyus Jones), a trio that in the title game beat a great Wisconsin squad constructed much like Krzyzewski’s Duke teams of old. You can’t blame Coach K for thinking that the 2015 title was proof positive that loading up on one-and-dones was the way to win in the modern era of college basketball.

That’s how we got to where we are today, where fresh off the most disappointing season of his career, Coach K has dipped back into the one-and-done well with a 2017 recruiting class that is even more loaded than the one that preceded it. The same Capel who claimed in 2014 that Duke wasn’t “going to be a team that’s going to recruit a whole class of one-and-dones” is now primed to have recruited three classes in four years in which three or more players leave for the NBA following their freshman seasons. Krzyzewski is no longer taking a page from Calipari’s book when it comes to recruiting—he’s taking the whole damn book.

While my gut reaction says it’s bizarre to see a legendary coach abandon the approach that lifted him to the top, especially so late in his career, it could be argued that Krzyzewski's willingness to change things up at this phase shows precisely what makes him so great. Stubbornness is poison in a college basketball coaching profession that demands innovation and adaptation, and Coach K winning five national championships (1990-91, 1991-92, 2000-01, 2009-10, and 2014-15) with drastically different rosters goes a long way toward making the case that he’s the greatest to ever do it. And it’s not like his experimentation is coming by way of the Grinnell system. All Krzyzewski is really doing is recruiting the best amateur talent that the world has to offer, a goal that every other coach in America has, too.

Still, it’s not hard to identify the players who are likely to stay in Durham for only one year, and relying so heavily on these types of guys comes at a cost. Since the 2010-11 campaign, when Irving became the first Duke player in the one-and-done era to use the school as a predraft pit stop, the Blue Devils have won zero regular-season ACC titles and made it to the Elite Eight just twice—with the aforementioned 2014-15 group and with a 2012-13 squad that started three seniors and is the only Duke team during that span to not have a one-and-done on the roster. This can’t be a coincidence. The one-and-done game asks you to push all your chips to the middle of the table with the promise of winning everything, only to hand you an up-and-down regular season, an early NCAA tournament exit, and an invitation to try again next year. Sure, every so often you can hit it big, like both Duke (which won the national title) and Kentucky (which started 38-0 before losing to Wisconsin in the Final Four) did in 2014-15. But is that worth the inconsistency? Is it worth enduring the headaches that come with coaching a perpetually inexperienced team? Is undermining a culture that took decades to build a fair price for one national title in seven years?

I suspect Krzyzewski (and most Duke fans) would say that it is, and they’re probably not wrong. But with Coach K’s retirement coming sooner than anyone wants to admit, I can’t help but wonder what this means for the program’s future. After all, the long-prevailing thought that Krzyzewski’s eventual successor would be a “Duke guy” can now be thrown out the window. What even is a Duke guy anymore? Do former assistants Steve Wojciechowski and Chris Collins really represent what this version of the Blue Devils has become? What’s the point of bringing in someone like Bobby Hurley, Tommy Amaker, or Johnny Dawkins if the culture they’re supposed to understand no longer exists? The only logical Duke guy to take over at this point is Capel, but is the winningest coach in men’s college basketball history really going to be replaced by someone whose head-coaching accolades to this point can be summed up with the words “Blake Griffin”?

Duke once appeared to have an obvious succession plan (Wojciechowski) lined up for the day when Coach K departs, but Jeff “Littlefinger” Capel has turned the situation into something resembling Game of Thrones. Capel’s recruiting prowess has fundamentally changed the Blue Devils’ forecast, pushed him to the top of the candidates list, and opened up the door to a whole slew of outsiders. Now there’s no telling how the most anticipated coaching search in the sport’s history is going to pan out. I could see Capel getting his shot or Duke sticking with the original Wojo plan. I could see Billy Donovan or Tony Bennett taking a job that was finally too good to pass up. I could see Sean Miller leaving Arizona for Duke after losing in the 2023 Elite Eight, and I could see Archie Miller choosing to return to his Tobacco Road roots after a successful tenure at Indiana. I could see Brad Stevens’s name popping up, only because no article about coaching searches would be complete without it. Hell, I’m not sure that I’m joking when I say that I could see Duke trying to hire someone like Kobe Bryant, Steve Nash, Dirk Nowitzki, or Shane Battier.

All I know for sure is that we are currently amid the most interesting era of Duke basketball ever and that the twists and turns set to unfold over these next five years will impact the program for decades to come. In the meantime, the first year of that five-year window features a Blue Devils team whose four most talented players will be freshmen, which could have anywhere from four to six first-round NBA draft picks, and which is the overwhelming favorite to win the national title despite having major concerns about defense and point guard play. That’s right, folks: After back-to-back years of falling back to not being back, Duke is officially back.