If I were to list a top 5 players to look at for, in no particular order, I would say be on the watch for:
Bubba Watson: the only 3-time PGA Event winner this season and is 4/4 in cuts made at the Greenbrier.
Tony Finau: has a T13 and T7 finish here, as well as a strong performance at the U.S. Open (solo 5th). Expect a well rested Finau to be ready to attack this course.
Phil Mickelson: finally coming back after all the drama he caused at Shinnecock Hills, Phil has had plenty of time to digest his golf game. With seven top-15 finishes in his last 12 starts, expect the Greenbrier ambassador to be eager to prove to the golf world he can make highlights other than from hitting putts when the ball is in motion.
Webb Simpson: this man LOVES this course. He has three top-10s and a T14 last year at this course. As well as a T10 finish at the U.S. Open a couple weeks ago, Simpson should be able to handle these challenging greens as he currently ranks T8 in strokes gained: putting.
Joaquin Niemann: This amateur has taken the Tour by storm this season. In only 7 starts, he has three top-10s and a T17 last week at the Quicken Loans National. Although he has inexperience, it hasn't seemed to have phased the amateur.