Andy Murray, seen here in Cincinnati last week, looks up to the U.S. Open draw gods and wonders what he did to anger them. (Photo by Jonathan Moore/Getty Images)

It's not as though Rafael Nadal is a slam-dunk to win in New York. Far from it, even if the last three times he has played it he has reached the final once and won it twice, including a year ago.

So his not-surprising decision to miss it leaves a hole and none of the top contenders, from a tennis point of view, would be too upset to see his name missing from the draw.

On summer form, this is a wide-open event. Top seed Novak Djokovic was sort of a newlywed ghost during his two rather brief appearances in tuneup events in Toronto and Cincinnati. No. 3 seed Stan Wawrinka still seems to be suffering some late Australian Open reverb, because he's not anywhere close to the player he was in January when he became the first outside the "top group" to pull off a major.

In form? No. 2 seed Roger Federer. And Frenchman Jo-Wilfried Tsonga, the No. 9 seed, who won the Canadian event in Toronto and defeated four top-10 players to do it.

Canadian Milos Raonic also is in good form despite a lopsided loss to Federer in Cincinnati. He won the ATP 500 event in Washington, D.C., reached the quarter-finals in Toronto and the semi-finals in Cincinnati. That was good enough to win the "U.S. Open Series" crown. And he does not have Federer, against whom he is now 0-6, in his half.

Here are the paths to the final four for some of the contenders; we grade them from A to D (A being the relatively easier draw, D being a tough one).

Paths to the final four

[1] Novak Djokovic

Diego Schwartzman (ARG) -----> Gilles Muller (LUX) -----> [28] Garcia-Lopez / Querrey -----> [13] John Isner -----> [8] Murray / [9] Tsonga -----> [3] Wawrinka / [5] Raonic.

Draw grade: C-. Potentially three big servers in a row in Muller, Querrey, Isner. Then possibly the winner of Murray and Tsonga. Big challenge.

View photos Why is this man smiling during a practice session at the U.S. Open Thursday? Take a look at his draw. (Photo by Chris Trotman/Getty Images for USTA) More

[2] Roger Federer (SUI)

Marinko Matosevic (AUS) -----> Sam Groth (AUS) -----> [25] Ivo Karlovic (CRO) -----> [15] Fognini / [17] Bautista-Agut -----> [7] Dimitrov / [20] Monfils -----> [4] Ferrer / [6] Berdych

Draw grade: A. We're not handing him the trophy just yet. But no Djokovic in his half, no Tsonga, no Murray, and a potential quarter-final opponent against him he has a crazy-good record either way. And we know he can handle the big servers. It's all there for him.

[3] Stan Wawrinka (SUI)

Jiri Vesely (CZE) -----> Nicolas Mahut (FRA) -----> [30] Jérémy Chardy (FRA) -----> [16] Robredo / [21] Youzhny (or Kyrgios or Pospisil) -----> [5] Milos Raonic (CAN) -----> [1] Novak Djokovic (SRB)

Draw grade: B. It doesn't seem quite as potentially routine as Federer's draw, and it can't ever be an "A" simply because Wawrinka isn't playing that well. But it's not bad.

[5] Milos Raonic (CAN)

Qualifier -----> Benjamin Becker (GER) -----> [29] Lukas Rosol (CZE) -----> [10] Kei Nishikori (JPN) -----> [3] Stan Wawrinka -----> [1] Novak Djokovic (SRB)

Draw grade: B+. A healthy Nishikori – and that's a question mark – is the type of player who could give him fits in the round of 16.

Robin Haase (NED) -----> Radek Stepanek (CZE) -----> [31] Fernando Verdasco (ESP) -----> [9] Jo-Wilfried Tsonga (FRA) -----> [1] Novak Djokovic (SRB) -----> [3] Wawrinka / [5] Raonic

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