If "90 percent of tennis is half mental" (to slightly misquote Yogi Berra), then Rafael Nadal lowered his chances of winning a ninth Roland Garros title by a few percentage points when he stated the following before the start of the spring clay court season:

"I'm not going to win 14 [titles in a row]. There's a start for everybody and there's an end. I know that I'm not going to keep winning all the tournaments on clay forever, and [there is] going to arrive a day when I'm not going to win one more … hopefully not yet."

And every good Minnesotan said, "Now that's interesting."

The European clay court season is the time of year when Nadal has dominated — no, obliterated — the tour as no player ever has: eight titles in Monte Carlo, the same in Barcelona, six in Rome, three in Madrid and eight at Roland Garros. If Rafa didn't win one of these tournaments in a given year, it was likely because he hadn't entered.

So what's his point — that we shouldn't expect him to hoist the French trophy at age 50? Well, ha, ha, ha. He couldn't do that! Or could he?

Such is the mystique of Rafael Nadal. Just shy of 28 years old, he has attained such otherworldly status on clay that no one could presume to know the how long and the how many of his career. The sun seemed to be at high noon over his clay court empire. No one was even contemplating dusk. So for the "Rey of Clay" to suddenly inform us that he, too, is going the way of all flesh?

Transparency is a wonderful quality, but tennis doesn't offer any trophies for it.

Rafa found that out soon enough when his results this spring tracked his confession. He lost in the quarters of Monte Carlo and Barcelona. He won Madrid, but only barely after his final-round opponent retired with an injury. He lost in the final of Rome. This still would be an amazing clay court season for anyone … anyone except Nadal.

A reporter asked him in Rome to explain his unprecedented struggles on clay. Would he blame an injury? Were his shoes not fitting? Strings too loose? After all, super-champions rarely admit decline, even to themselves.

"Get used to [it]," Nadal said. "Because with the years it is the normal thing, and in the end everybody suffers. It's part of the sport. It's part of the careers of everybody."

This may be admirable realism, but here is how every player in the locker room interpreted his words: "Hmmm, maybe I can beat Nadal on clay."

One rarely wins a tennis match without the belief it can be done. Rafa's invincible reputation on clay has been every bit as much of a weapon as his fearsome forehand and tenacity. Over his career, a great majority of his opponents have awakened lacking the belief that they could conquer him. And then they went out and proved themselves correct.

But now players are smelling blood. Not the least of whom is Rafa's main rival, Novak Djokovic. Last year, Djokovic effervesced that beating Nadal in the final of Monte Carlo was one of the highlights of his career. Last week, Novak beat Rafa in Rome and it was no big deal.

Contrast Rafa's mindset to that of another superstar, 33-year-old Serena Williams, who after winning Rome painted this metaphor: "I am like fine wine, my tennis is getting better with age." She won't be taking home the humility award, but she will be entering Paris full of confidence in defense of her title. With her ongoing domination of the tour, there is no reason to think she won't.

As for Nadal, maybe he is just attempting to transfer expectations to someone else. If so, he's accomplished that — world No. 1 Djokovic enters the only major he has never won as the slight favorite. Still, Rafa has lost just one match in nine years in Paris. Three out of five sets is his favored distance. Court Chatrier is his happy place. Surely, Rafa has not gone crazy.

Or maybe he's just crazy like a fox.

During his 13-year professional career, Minnesota's David Wheaton reached the third round in singles and semifinals in doubles at the French Open. David is now a radio host and author. Find out more at davidwheaton.com.