I've discovered a fascinating six-part series at CBSSports.com that wonders who could replace the six active college basketball coaches that are in the Hall of Fame.

They've made it to John Calipari at UK, who was inducted into the Naismith Basketball Hall of Fame in 2015.

I've often wondered this myself since the Kentucky job is not only--and arguably--the best job in college basketball, but also the toughest.

There is no microscope like the one under which any UK coach operates.

Calipari is, was, and continues to be tailor-made for that kind of scrutiny. Every kind of criticism rolls right off his back.

But the CBS blog is more interested in how long he's going to be there and they feel it is until he retires from coaching altogether.

They and I have long since given up the idea that he's returning to the NBA. With every passing season, that seems less and less likely.

The CBS take is a supposition that he does this about 10 more years. At that time, he'll be 69 years old.

And with coaches now working into their 70s more than we've ever seen before, it could be a few more years for Calipari.

That begs the question, "Who will be the hot coach at that time?"

It's nearly impossible to answer that question with any accuracy at this time, but CBS takes a stab anyway and puts Billy Donovan at the top of the list.

The former Florida coach and current Oklahoma City Thunder coach has won two NCAA titles and has taken the Thunder to each of the past three NBA Playoffs.

But NBA success can erode quickly for some. If that were to happen to Donovan, he could make a return to college hoops and get any job he wanted. And, at Kentucky, he'd actually get a RAISE.

Also, unlike, say, Duke or North Carolina, Kentucky won't feel the need to hire from within the "Kentucky circle."

When the time comes, UK will want to hire a big name who WINS. Period.

It's a fascinating piece containing speculation about coaches who are experiencing great success now.

But what happens THEN?