Armageddon for the big four? Could be

Is it Armageddon for the big four, mere weeks after that designation finally became fully credible with Andy Murray's win at the U.S. Open?

It's unlikely, but think about it for a moment.

Roger Federer pulled out of the Paris Masters 1000 just hours after he lost the Basel final on his home court to Juan Martin del Potro. That match lasted 2 hours, 44 minutes.

Federer said he was skipping the "mandatory" Paris 1000 because it was "too much" and he had "niggling stuff" to address before next week's World Tour Finals in London. But it was just the 11th match Federer has played since he lost in the quarterfinals of the U.S. Open. And he took that decision even though he still had a long-shot chance at retaining the No. 1 ranking despite trailing Novak Djokovic by a significant margin in the race standings.

It's understandable that Federer wants to be fit and healthy when he defends his WTF title; it's the biggest tournament after the four Grand Slams. But one of the big takeaways from this is that he's 31 years old and increasingly interested in conserving his energy. Allowing Djokovic to finish the year at No. 1 without fighting it out to the bitter end may be wise, but it's also a sharp comment on Federer's diminishing options.

Then there's Rafael Nadal. He's resting his knees, as he has been since way back in early July, when he lost in the second round at Wimbledon. Sure, Rafa expects to return as good, if not better, than ever. He and his team claim that the "conservative" (read "no surgery") approach they elected to take is working, and he ought to be back as good as new.

But Rafa's knee problems appear to be chronic and use-related. His problem is that if he's going to vie for the No. 1 ranking, he's also going to be abusing those knees. There's no two ways around it. We have to wait and see, but the reality is that Rafa is a huge question mark.

And how about Novak Djokovic? He's been in all four Grand Slam finals this year, which is a great achievement, even if he won just one of them (the Australian Open). He's guaranteed the year-end No. 1 ranking. He's won more matches (70-12) than any of his peers.

But Nole was upset in his first match at the Paris Indoors by Sam Querrey, an American player who was ranked outside the top 100 this spring (thanks mainly to injury-related layoffs and loss of form) but is now back and knocking on the door of the elite top 20 (he's No. 23, six ticks off of his career best).

Djokovic is struggling with "personal" problems, some of them undoubtedly related to the health of his father, Srdjan. Nole won't comment on those matters, but at times the well-publicized, if not well-explained complications in his life hark back to the days when Djokovic was an enigma, distracted and sometimes seemingly ill-affected by the circumstances of his life and career.

That left Murray as the final and most junior member of the big four still in contention in Paris, but it was only because the U.S. Open champ and Olympic gold medalist had yet to play a match. He finally got out of the starting blocks Thursday -- and was promptly beaten, and roundly so, by up-and-coming 21-year-old Jerzy Janowicz of Poland.

No player outside the current big four has won a Masters 1000 event since Robin Soderling took the Paris title in 2010. The new statistic on everyone's lips must be that this is the first event featuring the big four in which none of them won even a single match. Full disclosure: I didn't even research that. You want to call me on it?

OK, we all know we'll see plenty more of all four of the icons who skipped or fell by the wayside in the first round of the final Masters 1000 event of the year. But it's also possible that we're approaching some kind of tipping point, where the future may hold many different and exciting things -- but being able to boast of a big four will not be one of them.

There's a lot of talent backed up behind the dam created by the elite quartet. In addition to the usual suspects (a rejuvenated del Potro, increasingly consistent Tomas Berdych and Jo-Wilfried Tsonga), we have fresh faces like Milos Raonic, Querrey and Janowicz. If you saw the Janowicz-Murray match, you may agree that Janowicz has a remarkably versatile and crafty game. You could lop off six inches from his 6-foot-8 frame and he'd still look like top-10 -- or better -- material.

Appreciate and enjoy the big four while you have them; you know the old saying: You don't know what you've got 'til it's gone.