5 storylines to watch at the 2017 US Open

We've come to the last leg of the 2017 Grand Slam season, and only a fortnight in Flushing Meadows remains on the docket. With injuries, absences, and uncertainty abounding, the year's final major could go any number of ways, and should be anything but predictable.

Here are five storylines to keep an eye on at the US Open.

How's your health?

At this late juncture of the season, with eight months of tournaments and three Slams in the rearview, wear and tear have caught up to people. Perhaps that's why - unlike the majors that come earlier in the season - the US Open has produced some sporadic results in recent years. On the men's side, there hasn't been a repeat winner since 2008, and seven different men have won the title since then. On the women's side, the last three years have produced six different finalists. The most successful players in New York tend to be the freshest, or the most resilient.

It's anybody's guess who that'll be this time around, in a year that's amassed the most dramatic late-season body count in memory, specifically on the men's side. Call it a consequence of the paucity of youth atop the ATP.

Both of last year's finalists - Novak Djokovic and Stan Wawrinka - are out, as is reigning semifinalist and 2014 finalist Kei Nishikori, as well as 11th-ranked Milos Raonic. Roger Federer, Andy Murray, and Marin Cilic - who've won the tournament seven times between them - are all carrying lingering ailments that forced them out of last week's Cincinnati Masters. Rafa Nadal has looked worn down this summer after a dominant first half of the season.

This year, more than ever, the US Open is shaping up to be a war of attrition. Who can stay standing the longest?

Can Muguruza turn down the noise, tame New York?

Garbine Muguruza rolls in as the tournament favorite, despite having never escaped the second round and having won just two main-draw matches in four career US Open appearances. But there's good reason to believe Muguruza can justify her billing and break from her recent history at Flushing Meadows.

Unlike the past two years, when she immediately followed up major career breakthroughs (making the 2015 Wimbledon final and winning the 2016 French Open title) with extended swoons, the Spaniard has built on her Wimbledon triumph this season with a scorching summer on the hard courts. She made the semis in Stanford and the quarters in Toronto, then romped to the title in Cincinnati, finishing with back-to-back beatdowns of the two top-ranked players in the world.

With her combination of power and athleticism, Muguruza is basically the platonic ideal of a baseliner; someone who can win with offense and defense. And she's been harnessing those capabilities with heretofore unseen consistency of late. Finally finding success in New York may simply depend on her ability to block out all the noise. Literally.

"It's a noisy city," Muguruza said of her struggles in the Big Apple. "Every year I go to the US Open and say, 'OK this year I am going to do better' but it never comes. I want to go there and change that. Hopefully this year I can do it."

Waiting for Fedal

Though one is 36 and the other 31, and though neither comes in looking close to his best, the path to a first-ever US Open meeting between Federer and Nadal has rarely been this clear. With no Djokovic, Wawrinka, Nishikori, or Raonic; a hobbled Murray and Cilic; and a muddled middle-class morass behind them, the two will likely never get a better chance to complete this one unfinished chapter of their storied rivalry.

They were drawn into the same half, so if they do clash it'll be in the semis, not the final. That's a bit of a bummer, but it also makes it more likely they'll manage to find each other in the crowd.

Nadal's ranked No. 1 for the first time in three years, and, as spotty as he looked on hard courts the past few weeks, he should be able to emerge from a pillowy eighth of the draw. Grigor Dimitrov could mean trouble in the quarters, but the Bulgarian has never made it that far in New York, and has beaten Nadal just once in nine tries. Federer has a tougher road, with a test against rising youngster Frances Tiafoe right off the bat, and landmines like Sam Querrey, Nick Kyrgios, and Juan Martin del Potro lurking in his quarter.

For all that, they should both be solid favorites to make it through to the semis, and given the historic bounce-back seasons both have had, an unprecedented US Open meeting would feel only fitting.

Halep takes another bite at the apple

For the fifth time this year, Simona Halep enters a tournament with a chance to become No. 1 in the world. Three times she's gotten to within one win of the top ranking. Twice she's been one set away, and once two points away. Each time, she's come up short.

Halep's season has been a bit of a paradox that way. She keeps putting herself in these situations, so she's obviously doing something right. But then, at the very moment everything seems to be lined up for her, something always seems to go wrong. Her inability to punch through has grown increasingly vexing and difficult to explain.

Taken as a whole, her 2017 has been consistently excellent; she's reached at least the quarterfinals of every event she's played since March, a 10-tournament run that includes six semifinal appearances and four finals. But it's also been somewhat disappointing; she's won just one title, and her consistency hasn't really held up from one match to the next. (The combined scorelines from her losses at her last two tournaments, for instance: 1-6, 1-6, 1-6, 0-6.) Some of her wounds have been self-inflicted, and some have been caused by circumstances beyond her control, but whatever the reason, the top ranking - like her elusive first Slam championship - has remained just barely beyond her grasp.

It's once again within palm's reach in New York. Though she comes in ranked No. 2, she leads the field in ranking points when last year's US Open totals are taken off, meaning she's effectively trying to maintain her position at No. 1 rather than chasing it. She could very plausibly hold it down just by making the second week. So naturally she drew Maria Sharapova - perhaps the most dangerous floater in the women's bracket, and owner of a 6-0 lifetime record against her - as a first-round opponent.

But escape that daunting opening match, and Halep's draw should actually open up nicely. From there, she'd have as good a shot as anyone to go all the way, and cross both long-sought items off her list in one stroke - as she so nearly did at the French Open. She's been dogged by almosts for a while. Is this when she finally puts them to rest?

Filling the men's tennis power vacuum

If there's a silver lining to all the injuries that have plagued the men's tour this year, it's that they've opened the door for some young blood, and allowed some outsiders to get a taste of life behind the velvet rope.

Alexander Zverev, 20 years young, is tied for the tour lead in 2017 titles, including two Masters 1000s that he won by beating Djokovic and Federer in the finals. He's still yet to prove his body can withstand the rigors of best-of-five play for two weeks, having never advanced past the fourth round at a Slam. But he's seeded fourth at the US Open, and is in the gimpy Murray's half of the draw, with perhaps the most straightforward path to finals of any top player.

The once-forlorn Dimitrov has long been an avatar for the so-called Lost Generation, but he's been resurgent this season, and just captured the biggest title of his career. He very nearly took down Nadal in Australia a few months ago, and could get another crack at him in short order. Nick Kyrgios just played in a Masters final! And if he can stay on the court, and tap into his elusive reservoir of motivation - as he did in Cincinnati - he's as big a threat as anyone to topple Federer, who he could face in the fourth round.

Federer, Nadal, and Murray can still ensure the outcome of this tournament winds up looking familiar. But with no buffer standing between their established order and the invaders at the gates, old and new could be set to clash in a way we haven't seen in some time.