Former No. 1 ranked player in the world Martin Kaymer jumped out to an early lead at the Players Championship with a nine-under par 63.
He posted seven birdies on the front nine for a 29 and added two more on the back for his low round.
Two-time PGA Tour winner Russell Henley held the lead for most of the day with a seven-under par 65, but Kaymer, playing in the afternoon groups slipped past him.
In the four-year span 2008-2011, Kaymer won 10 European Tour events including the 2010 PGA Championship at Whistling Straits. He became the No. 1 ranked player in the world, when he finished runner-up at the 2011 WGC-Accenture Match Play to Luke Donald.
He held the top spot for eight weeks and his last win came in November, 2011 at the WGC-Champions in China.
Kaymer predominantly played a fade and felt he needed to learn to hit a high draw to win major championships. The swing changes completely altered his game and he has not been the same player for the last two years.
He finished T-8 at the WGC-Champions last November, but missed two cuts and has not had a top-10 finish in his last eight starts. He finished T-18 last week at the Wells Fargo in Charlotte, North Carolina.
Henley already has one win this season at the Honda Classic, where he held on to beat Rory McIlroy and Russell Knox in a playoff. He added another top 10 at the Shell Houston Open, but missed his last two cuts prior to the Players.
Sang Moon Bae has not been having his best season on tour. He does not have a top-10 finish and with only $456,000 in earnings is No. 97 in the FedEx Cup race.
He played well on Thursday, with two birdies and an eagle to go with a lone bogey on the front nine. He made three more birdies on the back nine for his six-under par 66, good for solo third.
Lee Westwood, Justin Rose, Sergio Garcia, Jordan Spieth, Brian Stuard, Gonzalo Fernandez-Castano, Gary Woodland and Scott Stallings are all tied for fourth at five-under par.
Ernie Els and Dustin Johnson are near the lead after one round at four-under par.
Zach Johnson, Bubba Watson, Jason Dufner and Graeme McDowell are in another large group at three-under par and T-18.
Rory McIlroy started on No. 10 and turned his first nine holes in three-under par 33, with four birdies and one bogey. He once again struggled to post a good score with bogeys at three of his last six holes. He finished at one-under par and T-29.
Phil Mickelson continued his struggles and is T-112 at three-over par along with Brandt Snedeker, Webb Simpson and three-time winner this season, Jimmy Walker.
It appears the cut will come at around one-over par on Friday. Luke Donald, Thomas Bjorn and Hunter Mahan are all at that number and will be looking to improve in the second round.