San Francisco - Top seed Rory McIlroy has been grouped with three highly-rated Americans for this week's WGC-Cadillac Match Play Championship in San Francisco.
A draw on Monday put Northern Ireland's world number one up against reigning FedExCup champion Billy Horschel, seven-times PGA Tour winner Brandt Snedeker and major champion Jason Dufner in round-robin play starting on Wednesday at TPC Harding Park.
The Match Play Championship, the first of the season's elite four World Golf Championships (WGC) events, was a knockout event from its inception in 1999 until last year, which meant that many of the big names were sent packing on the first day.
Therefore, the format was tweaked this year in an effort to give top seeds a chance to overcome one bad match.
Masters champion Jordan Spieth, the second seed in the field of 64, drew Englishman Lee Westwood, American Matt Every and Finn Mikko Ilonen.
Spanish 10th seed Sergio Garcia was drawn in an all-European group with Jamie Donaldson, Bernd Wiesberger and Tommy Fleetwood.
"It's an all-European group so it will be pretty friendly I think but no easy matches," Donaldson told Golf Channel.
Defending champion Jason Day of Australia is grouped with American Zach Johnson, South African Branden Grace and American Charley Hoffman.
The top player in each of the 16 four-man groups was awarded to players based on their position in the world rankings while the rest of the group was filled through a random draw.
Each golfer will play the other three men in his group in 18-hole match play over the first three days. The top player from each group will then advance to the final 16, when the event will become sudden death.
Two big names already missing are Tiger Woods and Phil Mickelson. Woods did not qualify, while Mickelson has withdrawn for personal reasons.
WGC Matchplay groups:
Rory McIlroy (1), Billy Horschel (19), Brandt Snedeker (36), Jason Dufner (56)
Jordan Spieth (2), Lee Westwood (27), Matt Every (41)4, Mikko Ilonen (68)
Henrik Stenson (3), Bill Haas (23), Brendon Todd (42), John Senden (60)
Bubba Watson (4), Louis Oosthuizen (29), Keegan Bradley (33), Miguel Angel Jimenez (63)
Jim Furyk (5), Martin Kaymer (17), Thongchai Jaidee (44), George Coetzee (59)
Justin Rose (6), Ryan Palmer (22), Anirban Lahiri (34), Marc Leishman (56)
Jason Day (7), Zach Johnson (24), Branden Grace (38), Charley Hoffman (49)
Dustin Johnson, Victor Dubuisson (21), Charl Schwartzel, Matt Jones (58)
Adam Scott (9), Chris Kirk (25), Paul Casey (36), Francesco Molinari (64)
Sergio Garcia (10), Jamie Donaldson (30), Bernd Wiesberger, Tommy Fleetwood (54)
Jimmy Walker (11), Ian Poulter (27), Webb Simpson (46), Gary Woodland (50)
J.B. Holmes (12), Brooks Koepka (19), Russell Henley (45), Marc Warren (51)
Rickie Fowler (13), Graeme McDowell (32), Shane Lowry (47), Harris English (55)
Matt Kuchar (14), Hunter Mahan (31), Stephen Gallacher (41), Ben Martin (61)
Patrick Reed (15), Ryan Moore (28), Danny Willett (48), Andy Sullivan (57)
Hideki Matsuyama (16), Kevin Na (20), Joost Luiten (43), Alexander Levy (52)
(The groups play among each other in a round-robin format to determine the winner, with playoffs likely. Then a bracket-style tournament continues with the winners of Group 1 and 16 facing off, their pairing off based on ranking).