Rory McIlroy, of Northern Ireland, walks off the second green during the final round of the U.S. Open golf tournament at Chambers Bay on Sunday, June 21, 2015 in University Place, Wash. (AP Photo/Ted S. Warren)
Rory McIlroy, of Northern Ireland, watches his tee shot on the fourth hole during the first round of the U.S. Open golf tournament at Chambers Bay on Thursday, June 18, 2015 in University Place, Wash. (AP Photo/Matt York)
Rory McIlroy, of Northern Ireland, warms up on the range before a practice round for the U.S. Open golf tournament at Chambers Bay on Tuesday, June 16, 2015 in University Place, Wash. (AP Photo/Lenny Ignelzi)
Rory McIlroy, of Northern Ireland, hands Niall Horan from the band One Direction a club during the Par 3 contest at the Masters golf tournament Wednesday, April 8, 2015, in Augusta, Ga. (AP Photo/Matt Slocum)
Rory McIlroy, of Northern Ireland, tees off on the second hole during a practice round for the Masters golf tournament Wednesday, April 8, 2015, in Augusta, Ga. (AP Photo/Matt Slocum)
Rory McIlroy, of Northern Ireland, follows his shot off the second tee in the third round of the BMW Championship golf tournament in Cherry Hills Village, Colo., Saturday, Sept. 6, 2014. (AP Photo/David Zalubowski)
**FILE** Rory McIlroy of Northern Ireland hugs his father Gerry McIlroy after the final round of the PGA Championship golf tournament on the Ocean Course of the Kiawah Island Golf Resort in Kiawah Island, S.C., Sunday, Aug. 12, 2012. (AP Photo/Chuck Burton)
Rory McIlroy of Northern Ireland holds the Claret Jug trophy after winning the British Open Golf championship at the Royal Liverpool golf club, Hoylake, England, Sunday July 20, 2014. (AP Photo/Scott Heppell)
Rory McIlroy of Northern Ireland holds up the Claret Jug trophy after winning the British Open Golf championship at the Royal Liverpool golf club, Hoylake, England, Sunday July 20, 2014. (AP Photo/Jon Super)
Rory McIlroy of Northern Ireland celebrates winning the British Open Golf championship after the final round at the Royal Liverpool golf club, Hoylake, England, Sunday July 20, 2014. (AP Photo/Scott Heppell)
Rory McIlroy of Northern Ireland throws a ball into the crowd as he celebrates winning the British Open Golf championship after the final round at the Royal Liverpool golf club, Hoylake, England, Sunday July 20, 2014. (AP Photo/Scott Heppell)
Rory McIlroy of Northern Ireland chips onto the 6th green during the final round of the British Open Golf championship at the Royal Liverpool golf club, Hoylake, England, Sunday July 20, 2014. (AP Photo/Peter Morrison)
Rory McIlroy of Northern Ireland celebrates after playing an eagle on the 16th hole during the third day of the British Open Golf championship at the Royal Liverpool golf club, Hoylake, England, Saturday July 19, 2014. (AP Photo/Jon Super)
Rory McIlroy of Northern Ireland holds up his ball on the 18th green after his round on the first day of the British Open Golf championship at the Royal Liverpool golf club, Hoylake, England, Thursday July 17, 2014. (AP Photo/Peter Morrison)
Graeme McDowell, of Northern Ireland, watches his tee shot on the second hole during the first round of the U.S. Open golf tournament in Pinehurst, N.C., Thursday, June 12, 2014. (AP Photo/Chuck Burton)