Phil Mickelson Lee Westwood Brandt Snedeker

Paul Casey recorded 13 pars and five birdies, including three on the back nine, to finish -1 and tied for fourth at The Masters. He is still without a major title, but Casey inched closer to another goal: The Rio Olympics.

"Top 15 before July 11th ... ," he told Press Association Sport, when asked about his current priority. "... I would desperately like a Great Britain tracksuit."

Paul Casey

Casey's Augusta performance bumped his world ranking from 25th to 24th, but he needs to crack the top 15 to make the Olympic team. So, if the 24th-best player in the world can be left out of the Olympics, who actually goes to Rio? It's complicated. Here is the simplest explanation:

-- Sixty players will qualify for the Olympics, based on standings in the World Golf Rankings on July 11.
-- The top 15 players automatically qualify with a maximum of four players per country.
-- The rest of the field is selected based on the rankings with a maximum two players per nation (for example, if Nation X has players ranked No. 1, No. 2 and No. 16, only No. 1 and No. 2 get in).
-- At least one golfer from each geographical region (Africa, Americas, Asia, Europe and Oceania) are guaranteed a spot.

What does this all mean? It means a lot of the biggest names in the sport, in golf-rich delegations such as the United States, Great Britain, Ireland, Australia and South Africa will be left off the plane to Rio. Results from The Masters give us a chance to see how everything is shaping up two months from the final selection (Note: Rory McIlroy, who is from Northern Ireland, has announced he will represent Ireland in the Olympics. He also had the choice to represent Great Britain. English players can only represent Great Britain). Here's the top 15:

World Golf Rankings Top 15

Americans Patrick Reed and Brandt Snedeker are both in the top 15, but the U.S. is already at its maximum with Jordan Spieth, Bubba Watson, Rickie Fowler and Dustin Johnson. While Casey is chasing that No. 15 ranking by July, it is not that simple for Reed (No. 11) and Snedeker (No. 15). They are chasing one man right now: No. 8 Dustin Johnson.

Let's take a look at Nos. 16-35:

World Golf Rankings 16-35

Without any Spanish competition, Sergio Garcia is safe outside the top 15. However, other players are not so lucky. Although Zach Johnson, Brooks Koepka, Phil Mickelson, J.B. Holmes, Jim Furyk and Matt Kuchar can smell the top 15, these players can start thinking about the John Deere Classic in Silvis, Illinois, played the same weekend as the men's Olympic competition. They would have to pass Dustin Johnson and everyone in between to get a bid.

The American stars are not the only stars who find themselves blocked out. Former Masters champion Charl Schwartzel is No. 20 in the world, but fellow South Africans Louis Oosthuizen and Branden Grace block his Olympic dreams at the moment. Marc Leishman made a playoff at The Open Championship last year, but he is a far cry from fellow Australians Jason Day and Adam Scott.

And how about Lee Westwood? The Englishman reached World No. 1 in 2010 and would have qualified based on the Olympic criteria for the better part of the last two decades. He finished tied for second in this past weekend's Masters with Spieth, but Westwood is not close to getting a shot at a gold medal.

Outside of that top 35 we have already mentioned, more household names will be left home:

No. 44 Ryan Moore (USA)
No. 46 Billy Horschel (USA)
No. 48 Smylie Kaufman (USA)
No. 53 Jamie Donaldson (Great Britain)
No. 58 Charley Hoffman (USA)
No. 62 Ian Poulter (Great Britain)
No. 63 Jason Dufner (USA)
No. 66 Graeme McDowell (Ireland)
No. 74 Ryan Palmer (USA)
No. 77 Webb Simpson (USA)
No. 95 Luke Donald (Great Britain)
No. 97 Keegan Bradley (USA)
No. 98 K.J. Choi (South Korea)
No. 100 Hunter Mahan (USA)
No. 132 Padraig Harrington (Ireland)
No. 149 Davis Love III (USA)
No. 179 Retief Goosen (South Africa)
No. 218 Ernie Els (South Africa)
No. 475 Tiger Woods (USA)

For the record, Tiger Woods would have qualified for the Olympics from 1997-2010 and 2012-2013.

On the other side of this equation is a diverse array of global golfers who will get to take the course with names they cannot sniff on a normal basis. Below is the current list of golfers who would make the Olympic field if the qualification process ended today, April 11. How many of these golfers do you recognize (after the top 20)?

Olympic Golf Rankings 1

Olympic Golf Rankings 2

Olympic Golf Rankings 3

Some are big names who are bailed out by their countries not being dense in golf talent.

World No. 50 Victor Dubuisson (France) and No. 84 Francesco Molinari (Italy) have both won Ryder Cups, but many of their British and Irish teammates with higher rankings will not be in Rio. No. 29 Rafa Cabrera Bello (Spain), No. 41 Soren Kjeldsen (Denmark), No. 42 Bernd Wiesberger (Austria), No. 47 David Lingmerth (Sweden), No. 59 Thomas Pieters (Belgium), No. 67 Thorbjorn Oleson (Denmark), No. 82 Joost Luiten (Netherlands), No. 88 Ricardo Gouveia (Portugal), No. 114 Alexander Levy (France), No. 142 Alex Cejka (Germany), No. 187 Mikko Illonen (Finland) and No. 248 Roope Kakko (Finland) all Europeans without Ryder Cups, are all slotted to go to South America.

Other big names are saved by this rankings system. No. 56 Martin Kaymer won his second major at the 2014 U.S. Open, but he has not won since. Kaymer is declining in the rankings, but Germany's lack of golf prowess keeps him on the Olympic roster. Belgian Nicolas Colsaerts, who has won a Ryder Cup but has not made a cut at a major since the 2013 U.S., gets in at No. 251.

Brendon de Jonge of Zimbabwe has only qualified for one of the last five majors, but he gets in at No. 197 in the world. No. 210 Camilo Villegas, who peaked at No. 7 in 2008, will be at home in South America, representing Colombia.

Jordan Spieth Danny Willett

The rear of the Olympic crop makes Middle Tennessee State look like an NCAA tournament favorite. Mardan Mamat, qualifier No. 59, is a 48-year-old from Singapore. The world No. 364 has qualified for the British Open three times, missing the cut twice and getting disqualified for signing an incorrect scorecard once.

The current final qualifier is Siddikur Rahman, the "Tiger Woods of Bangladesh." He is ranked No. 373 and has never qualified for a major.

Part of the spirit of the Olympics is the diversity of nations. If the IOC took the best competition for golf, the participants would be a homogenous mix of the same American, British, Irish, Australian and South African stars we see on TV during most majors. Since 2005, only Kaymer (2), Angel Cabrera (2), Y.E. Yang and Michael Campbell have won majors and not been from one of those five Olympic delegations.

In Rio, Jason Day, Jordan Spieth and Rory McIlroy will tee it up with players who have only seen Augusta National in pictures.

Although two months remain before the field is locked, much of the roster appears set. However, for players like Paul Casey, The Masters served as a reminder some spots are still up for grabs.

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-- Follow Jeffrey Eisenband on Twitter @JeffEisenband.