For years now -- check that, decades -- the essence of Duke basketball and the existence of Mike Krzyzewski have been soldered. Singular. The two are one: more philosophical matrimony than employer-employee partnership.

You think Duke, you think K; you think K, you think Duke. He won't outlive the association. He built the program into a behemoth, turned the Blue Devils into the most hated-but-also-begrudgingly-respected college hoops team in history, and then somewhere along the way Krzyzewski became Duke Basketball in corporeal form. In retrospect, even his 10-year stewardship of USA Basketball felt like an extension of the Duke brand.

He's considered, by far, the most powerful man in college basketball. There is no replacing such a figure.

But someone has to follow him.

It's hard to envision how that's all going to go, but go it must. When? Nobody knows, and that's part of the compelling undercurrent with Duke. Krzyzewski's inevitable retirement will make for massive news, but who's to say if that's coming in 2020, 2026 or somewhere in between? If Krzyzewski has a vision for an end-game, he's kept those plans almost exclusively to himself and potentially his family. Retirement doesn't seem imminent -- not like we'd know that anyway; that can hinder recruiting -- but the man is 71. Krzyzewski is undeniably in the winter of his career, even as he continues to recruit at as high a level as ever.

But we will get to a day when Duke men's basketball is not run by Mike Krzyzewski, something that hasn't been true since March 17, 1980. Whenever that happens, it will be one of the more tracked and intriguing successions in college sports history. Truly, it could be the most pressure-packed assumption to the throne ever in college athletics.

CBS Sports is running a six-part series on the half-dozen men's college basketball teams that have active Hall of Fame coaches leading their respective programs. We're examining each coach and school's situation, how and when they might leave their posts, and reasonable candidates who could succeed them. This is more than a guessing game on who's next; the series is taking a big-picture look at the unique challenge facing each of the six schools. First up is an exploration of what awaits at Duke.

Timeline for Coach K leaving Duke

There's no telling when Krzyzewski will hang it up, and what about how he'll do it? Will he seek to give Duke the easiest transition possible by announcing it well before his final season? If that happened, it would prompt a commemorative farewell tour, which sources have told me is not something Krzyzewski is especially keen on having to go through.

There is the possibility of a John Wooden-type exit: Krzyzewski coaches out his final year at Duke in secret, only revealing his retirement plans at the very end of the season, if not a few days after it's over. Or perhaps he'll coach out his final season without certainty that it will be his final season as he goes through it. One source said Krzyzewski has reached such an age that he's taken to evaluating his program and the state of his life and career after the urgency and clamor of a season has passed. If that was the case, might we see a late April/early May sendoff?

When you're Mike Krzyzewski, there is no perfect day or month to cut ties. But so long as health issues don't impede the proceedings, whatever is done, K will aim to do it in a way that best stabilizes Duke. And yet: his health. He's had six surgeries in the past 2 1/2 years. Krzyzewski still seems quite active and energetic and ambitious in his post, but every time Duke announces a need for Krzyzewski to undergo a procedure, it surfaces questions about his shelf life as a coach.

How long can he go? Does K want to become the first coach ever at a major program, and one of the few men in history, to still be coaching basketball at 80? If he wants that, can he physically get there? If he can and does, it means Duke will still be coached by Mike Krzyzewski in 2027. That's mind-boggling to consider.

Age 71 Seasons Entering 39th at Duke, entering 44th overall Career record 1,027-279 at Duke; 1,100-338 overall Final Fours 12 NCAA Tournaments 34 NCAA titles 5 Hall of Fame induction 2001

Top candidates to replace Coach K

We're addressing this, of course, because in recent years the question of who will get the lone pleasure and unenviable pressure of succeeding K has become a real point of interest in college basketball circles. There probably isn't a job in college sports with more curiosity behind Who's Next. Given his stature, given that his name's on the damn court, given that he has a case for being the greatest coach in men's college basketball history, it's long been presumed that Krzyzewski will have significant say in his selecting his successor and that said successor will come from his coaching tree.

Who might that be, and will outside factors have significant influence on who ultimately takes the clipboard from Krzyzewski? Industry sources -- and those who have worked for K -- largely agree on the candidate pool at this stage. It's almost certainly going to be a former Duke player/Duke assistant and yet, it's almost definitely not going to be anyone currently on the Duke bench now. Duke assistants Nate James, Jon Scheyer and Chris Carawell are all yet to work as head coaches. There is a former K assistant who's found success, perhaps so much that he won't retreat back to college: Quinn Snyder, who's thriving with the Utah Jazz. He may be an NBA-only guy from here on out.

Duke has the pull to capture the attention of almost any huge name in basketball, but at this point, those targets aren't clear nor is the administration's intentions on looking outside the fraternity of Coach K.

So as of now there is a cram among the Duke alumni and at this point it's hard to forecast any true leader -- because the variables surrounding each candidate could be different two years from now, let alone four or five.

Marquette coach Steve Wojciechowski would be a natural fit at Duke. USATSI

1. Steve Wojciechowski

Currently: Coach at Marquette

Résumé: Wojciechowski, 42, is about to enter his fifth season with the Golden Eagles. He's made one NCAA Tournament and carries a 73-59 record. Wojciechowski starred at Duke, where he played from 1994-98 and earned the moniker "Wojo." He was the NABC Defensive Player of the Year in 1997-98. From 1999-2014, Wojciechowski was an assistant under Krzyzewski, making him one of the longest tenured assistants in Duke history.

Why it could be him: Industry sources in recent years have maintained a belief that Wojciechowski is a slight favorite to land the Duke gig. Krzyzewski's relationship with Wojo, dating back to his playing days, has long been acknowledged as one of his closest. Whenever Krzyzewski leaves, if Wojciechowski is in a position of reasonable success at Marquette, that could be his launchpad for a return to Durham.

Why it wouldn't be him: If Marquette continues to live life on the bubble and makes more NITs than NCAA Tournaments, it could affect Wojo's chances vs. other candidates who might come to have more consistent success as head coaches. Getting the Duke job will require more than Coach K's endorsement; the successor is almost certainly going to have to bring a good track record as a coach in a power conference.

2. Jeff Capel

Currently: Coach at Pittsburgh

Résumé: Capel has a 162-110 record, with previous stops at VCU (2002-06) and Oklahoma (2006-11). Capel made the Elite Eight in 2009 with a Sooners team led by Blake Griffin. His tenure at Oklahoma ended amid aftermath of recruiting violations made by his staff. Capel was never implicated in the wrongdoing; a rash of transfers ultimately torpedoed the program. He played at Duke from 1993-97 and served as an assistant to Krzyzewski from 2011-18.

Why it could be him: Capel, 43, has a lot of head coaching experience already and by the time Krzyzewski retires, he figures to have even more, so long as Pitt is succeeding. Plus, Capel's reputation as a recruiter of premier, five-star talent ascended in recent years as Duke continually landed top-two classes and competed with (while occasionally beating) Kentucky annually on the recruiting trail.

Why it wouldn't be him: If Capel's to be the guy, he needed to take another coaching job. And in Pitt, he's got a great opportunity -- with no assurances it works. If Capel winds up treading water or worse with the Panthers, it's considered unlikely that he'd be tagged as Krzyzewski's inheritor of the throne.

3. Chris Collins

Currently: Coach at Northwestern

Résumé: Is already a legend at Northwestern thanks to coaching the Wildcats to the program's first NCAA Tournament appearance in school history. That came in 2017 and included a win, to boot. Overall, Collins is 88-77 in five seasons at Northwestern.

Why it could be him: Frankly, if Collins winds up getting Northwestern back to a couple more NCAA Tournaments (and wins a few more games in the Big Dance), it's going to outshine any other candidates' résumé offerings with the exception of a Final Four appearance. Historically, Northwestern is so inept that if Collins is capable of keeping up in the Big Ten and making NU relevant, that's a huge accomplishment.

Why it wouldn't be him: Personally, I'm not outright convinced Collins, 44, would run to the Duke job -- or that he'd be in position to take it when it becomes available. Might he get intrigued at following in his father's footsteps instead? Doug Collins worked in the NBA for years, of course. Even if Chris doesn't get afforded a head job in the pros, maybe he'd try working as an assistant or in another capacity, even. His connections are deep and options seem to be plentiful.

4. Bobby Hurley

Currently: Coach at Arizona State

Résumé: Has a 92-67 record in five seasons as a coach, including taking the University of Buffalo to its first NCAA Tournament in school history in 2015. In 2017-18, Hurley got Arizona State to the NCAA Tournament and brought the program to a top-three ranking in the polls in December.

Why it could be him: Well, take it from Notre Dame coach Mike Brey, who's a former Krzyzewski assistant -- and the final Krzyzewski assistant to not be a former Duke player. Last season, Brey told me he thought Hurley's overall package was the best fit for Duke in its transition out of the Krzyzewski Age. Hurley, 47, is one of the best players in program history (he's still the all-time NCAA leader in assists) and was a key figure on Duke's first two national title teams in 1991 and 1992.

Why it wouldn't be him: Hurley burns hot, a character trait that's also, at times, a flaw. Then again, his outbursts against officials aren't too many shades removed from K, who's been known to chew a few ears. If Hurley remains a firecracker on the sideline to the point where it brings ASU some sour publicity, it could affect his chances. There's something else to consider: Hurley was never an assistant at Duke. After playing in the NBA, he worked under his brother, Dan, at Wagner and Rhode Island before getting the Buffalo job. Having not spent time on Krzyzewski's staff could be a defeating blockade.

5. Tommy Amaker

Currently: Coach at Harvard

Résumé: Amaker, 53, has by far the deepest coaching background of any candidate listed. He's been at Seton Hall, Michigan and Harvard, combining for 22 years (including this upcoming season) worth of experience. In that time Amaker's amassed a 387-257 record and made the NCAA Tournament five times, four of which have come at Harvard which, prior to Amaker's arrival, was unheard of.

Why it could be him: Amaker is similar to Johnny Dawkins, who is now coaching at UCF. Those two were the most important recruits of Krzyzewski's career in that their commitments to Duke wound up propelling the program to national prominence and a string of Final Four appearances in the 1980s. If Duke seeks to change the guard and wants someone who resembles Krzyzewski's image as a leader and puts an emphasis on an aged veteran to handle the immense pressure that comes with the job, Amaker would make sense -- so long as Harvard continues to play atop the Ivy League and make a few more NCAA Tournaments.

Why it wouldn't be him: Let's say Krzyzewski goes another five years. By then, Amaker is 58. Would Duke want to bring in a coach knocking on the door of 60 years old? Agism sometimes plays a factor in these hirings, especially at the biggest programs. What's more, Amaker's success at Harvard will not entirely overshadow his shortcomings at two much bigger jobs, albeit jobs he took perhaps before he was ready for them.

The takeaway

As you'll see with each of our installments in this series, the TBD timeline with retirement is the most critical factor in all of this. If Krzyzewski, for whatever hypothetical reason, is forced to retire nine months from now, the pool of candidates will probably be the names you see above. But if he goes until 2024, there could easily be a swap of two or three names off this list for others not mentioned. By then, guys like Scheyer and James could be in play.

What's figured to be automatic: Duke is going to exit the K era by extending his legacy with one of his former players. For as huge as the program is, and the fact it would get almost any coach to take its call, the biggest names in basketball are unlikely to be seriously courted here. Programs like Kansas and Kentucky will be in position to that. At Duke, they'll keep it within the brotherhood which, obviously, allows for no assurances that the program will be able to maintain its platinum status in the immediate years after arguably the greatest career in basketball coaching comes to an end.