It is an incredibly small slice of the population that is gifted enough to play a sport professionally. Take that slice and shave off a thin sliver for those who become champions. Once you get to the rarefied air of the all-time greats, you're talking about mere crumbs -- a tiny fraction of a tiny fraction of a tiny fraction.

That's probably why those conversations are so subjective, so difficult to quantify, and so addictively fun. And in mixed martial arts, no one else invites these conversations like UFC welterweight champion Georges St. Pierre.

Royce Gracie was an original. Chuck Liddell was the sport's first crossover star. B.J. Penn is an incomparable talent. Anderson Silva is a force of nature. Fedor Emelianenko is a cold-blooded wrecking machine. But, for my money, something about St. Pierre seems to capture imaginations in a way the others don't.

So is GSP the greatest fighter ever? That's a conversation for another day and time -- after all, the guy is still only 29 years old. But with a 20-2 MMA record going into a fight against Josh Koscheck this Saturday that would mark his eighth consecutive UFC victory and fifth title defense, I believe it is fair to ask whether he ranks as the greatest welterweight in mixed martial arts history. If you read the headline -- as I suspect you did -- you know where I stand.

Who is he competing against? Pat Miletich was a seminal fighter who defended the UFC strap four times, but he also lost seven times. Though he would (and, on occasion, has) fought at welterweight in today's UFC, Gracie made (and broke) his bones in the promotion's early days, when weight classes didn't exist. He is a pioneer, but comparing him here feels a bit like apples to oranges. Penn has some nice victories at 170, but will always be known primarily as a lightweight.

That leaves St. Pierre's only opposition as Matt Hughes. The 45-8 Matt Hughes.

Think about that for a second. Forty-five wins in mixed martial arts. St. Pierre hasn't appeared in 45 fights -- not even close. Hughes has the most wins all time in the UFC with 18. During two title reigns as welterweight champ, Hughes made a combined seven title defenses. With his physical brand of submission wrestling and thudding ground and pound, he paved the way for the modern mixed martial artist.

Enter Georges St. Pierre.

This comparison is a little like the one everyone makes between Jack Nicklaus and Tiger Woods. Or, at least, the one they made until Tiger Woods discovered bottle service. Jack has the numbers on his side, but everyone assume the metaphorical student's passing of the teacher is inevitable.

Regrettably, Jack and Tiger never fought each other (hey, there's still time). But UFC fans do have that luxury. Hughes took the first leg of the trilogy between himself and GSP, but a head kick and an armbar later, St. Pierre had taken two of three. St. Pierre may not -- heck, may never -- have Hughes' win totals, but he has the indisputable head-to-head record.

That fact alone might be enough for some to give St. Pierre the GOAT label. But there's more, too. If he GSP beats Koscheck this Saturday -- a big if, to be sure -- he will match Hughes' longest streak of title defenses. Hughes reached that mark in his 38th MMA fight. St. Pierre will have done it in 23.

It's also worth noting St. Pierre's history versus those welterweights who have beaten him, or even given him a good fight. After losing to Hughes by armbar (and taking a ribbing for it later from Hughes), GSP trained even harder and came back better. He won the rematch by TKO and the rubber match by -- you guessed it -- armbar. After the shocking upset to Matt Serra, St. Pierre learned his lessons and dominated Serra in the rematch, eventually forcing a referee stoppage due to knees to the ribs (and it still makes me wince). After winning a controversial decision over Penn, GSP came back in the rematch and forced a medical stoppage in the fourth round. Penn's corner -- who crowed incessantly before the fight about GSP's weak chin and shaky constitution -- threw in the towel to save their fighter. If that's not the greatest welterweight ever, I'd love to hear the counter-argument.

But wait -- there's more. St. Pierre also represents a stylistic prototype for the next generation of fighters in this still-young sport. To paraphrase St. Pierre himself (speaking on Spike's "UFC 124 Countdown" show), he may not have the absolute greatest pedigree in any one of the several fighting styles in which he trains, but his true strength lies in putting all of them together. In other words, Georges St. Pierre is the first great mixed martial artist in the history of mixed martial arts.

Finally, St. Pierre has shown both a willingness and a desire to carry greatest-ever distinction, and that can't be discounted. Legacies take a certain amount of care and feeding -- carrying oneself in just the right way in and out of the cage, training properly, committing to a certain lifestyle, interacting professionally with media and fans, and aptly embracing the spotlight and expectations that such distinctions denote. To date, St. Pierre has handled all of those things, where the other welterweights really have not. GSP gets that there's more to a legacy than walking into a fenced-in cage, beating someone up, and walking out.

So in a way, St. Pierre's legacy is a lot like his fighting style: he has learned to put it all together in a way that his current and historical antecedents did not. And, of course, his record in the cage speaks for itself. If he loses to Koscheck this Saturday, perhaps he takes a hit. But something tells me that hit would be a temporary one -- that Koscheck would need to batten down the hatches. That's a champion -- a fighter who is undeniably great, win or lose, belt or not. And that's why Georges St. Pierre is the greatest welterweight of all time.