David Wheaton: U.S. Open is survival of the (remaining) fittest

Late August is upon us, and with it, all the regularities of a waning summer: pilgrimages to the Minnesota State Fair, a final sojourn at the cabin, Vikings fans anticipating the opener, and kids heading back to school.

Oh, and add one more to the list — tennis pros limping into New York for the U.S. Open.

From the first days of January, players have been traveling all over the world, training and competing week after week, desperately trying to win, and most especially at this time of the year, desperately trying to stay healthy.

After spending spring and early summer on natural surfaces like clay and grass where there is a bit of give and glide, players make the jarring transition to the hard courts of the American summer series of tournaments. And they start dropping like flies.

An overstatement? Consider that three of the four men's semifinalists at last year's U.S. Open — winner Stan Wawrinka, finalist Novak Djokovic and Kei Nishikori — will not even be taking the court due to injuries (in fact, they are done for the year). Neither will past champ Andy Murray, who unexpectedly withdrew Saturday because of a hip injury, or big-serving Canadian Milos Raonic. 2014 winner Marin Cilic will be in the draw, but this will be his first tournament since hobbling out of the Wimbledon final.

That makes six of the top 11 who are either nicked up or knocked out.

It's easy to blame the hard courts and the endless tournament schedule — and they certainly contribute — but truth be told, players' bodies are already groaning before they step foot Stateside. The traumatic tears and breaks that occur in contact sports like football and hockey are rare in tennis. More common are repetitive use injuries that come after the millionth forehand or lunge, causing elbows and knees to inflame. Simply put, players often push themselves beyond the invisible line dividing healthy from hurt.

Last year at this time, it was Federer who had called it a year because of injury. Six months on the sidelines for an athlete in his mid-30s may result in some renewed motivation, but surely no one, not even Roger, could have foreseen renewed domination. But that is exactly what has transpired this year for the Swiss — he has won two majors, in Melbourne and Wimbledon, bumping his record tally to 19 and putting himself in pole position to regain the No. 1 ranking.

Of course having most of his rivals down or out clears the way, but there are new contenders eager to fill the void. One is the 20-year-old German, Alexander Zverev, already No. 6 in the world and owning the same number of tour titles. He recently beat Roger in the final of Montreal, although it should be noted that Federer tweaked his back during the match, leading him to withdraw from Cincinnati the following week. How much that will factor into Federer's U.S. Open form is anyone's guess.

And then there is two-time champ and current world No. 1, Rafael Nadal. He is having a resurgent year of his own at age 31, winning his 10th French Open title in early June. But Rafa hasn't shown much since and may be lacking the momentum that typically precedes his major victories.

Injuries haven't decimated the women's field but the absence of Serena Williams, due to give birth soon to her first child, has provided some hints about who could take her place in the future. The current top four — Czech Karolina Pliskova, Romanian Simona Halep, Spaniard Garbiñe Muguruza, and Ukrainian Elina Svitolina — are all under 25 years old, but only Muguruza has been able to strike major gold — at the French Open in 2016 and Wimbledon in July.

More recognizable names to follow are two-time winner Venus Williams, who at 37 years old has climbed up to No. 9 with final runs at the Aussie Open and Wimbledon, and past champion Maria Sharapova, who is returning from a performance-enhancing drug suspension and injuries of her own.

And that's why we can't wait to watch.