PONTE VEDRA BEACH, May 11, 2014 (AFP) - Germany's Kaymer dropped into a tie for the lead with a bogey at the par-four 18th on the TPC Sawgrass Stadium Course, carding an even-par 72 for a 12-under total of 204.
The leading duo were three strokes ahead of Spain's Sergio Garcia and Australian John Senden.
"It was very tricky today, therefore, you didn't have as many birdie chances as the first two days," Kaymer said. "It played tough today.
"Even when you hit fairways, it was gusty and therefore a little bit difficult to attack the flags."
Garcia, the 2008 winner, fired a three-under par 69 while Senden posted a 68.
Aussie Matt Jones and George McNeill both posted 69s to share fifth place with Gary Woodland, who carded a 70 for 208.
Italy's Francesco Molinari matched the low round of the day with his five-under 67. He was joined in eighth place on 209 by Canadian David Hearn (68) and England's Lee Westwood (71).
Three of the four players who have a chance this week to supplant Tiger Woods atop the world rankings -- Henrik Stenson, Bubba Watson and Matt Kuchar -- were among a group of 11 players sharing 13th place on 211.
Sweden's Stenson posted a 70, as did America's Masters champion Watson, while Kuchar carded a 69
Stenson, ranked third in the world, has a chance to topple Woods, who has been idled by injury, with a top-six finish on Sunday.
Watson needs a runner-up finish while Kuchar needs a victory in the $10 million tournament to have a chance at the number one ranking.
World number two Adam Scott of Australia kept his hopes of move to number one for the first time alive with a third-round 69 that left him tied for 28th on 213.
- 'You never know' -
Scott would need a top-16 finish on Sunday to assume the number one spot, and he thought it might be possible with a relatively early tee time in the fourth round likely putting on the course in good scoring conditions.
"It's possible," he said. "I'll be off fairly early probably again, and try and sneak up there as high as I possibly can.
"You never know what's going to happen out here."
Spieth parred every hole on the front nine, with only three birdie chances from within 20 feet.
Kaymer, meanwhile balanced a three-putt bogey at the fourth with a nine-foot birdie putt at the sixth.
The 2010 PGA Champion got up and down for birdie from over the ninth green to stretch his lead to two strokes, and had eight straight pars before his closing bogey.
Spieth nabbed his first birdie at 11, sinking a four-foot putt to trim Kaymer's lead to one stroke.
He nearly chipped in for birdie at 13, but his ball hit the flagstick and landed two feet from the hole.
"I was all over the place and really got a lot of good breaks today," Spieth said. "And in order to win the golf tournament tomorrow, I'm going to have to drive the ball a lot better and give myself more looks at birdie.
"Today, I really got the breaks and got the bounces and made the three- and four-footers to stay alive. I'm not going to be able keep doing that."
Scores on Saturday after the third round of the $10 million US PGA Players Championship (par 72, USA unless noted):
204 - Martin Kaymer (GER) 63-69-72, Jordan Spieth 67-66-71
207 - John Senden (AUS) 70-69-68, Sergio Garcia (ESP) 67-71-69
208 - Matt Jones (AUS) 70-69-69, George McNeill 71-68-69, Gary Woodland 67-71-70
209 - Francesco Molinari 72-70-67, David Hearn (CAN) 70-71-68, Justin Rose (ENG) 67-71-71, Lee Westwood (ENG) 67-71-71
210 - Stewart Cink 70-70-70, Jim Furyk 70-68-72
211 - Ryan Moore 70-74-67, Brandt Snedeker 75-69-67, Matt Kuchar 71-71-69, Daniel Summerhays 74-68-69, Bo Van Pelt 71-70-70, Morgan Hoffmann 71-70-70, Bubba Watson 69-72-70, Henrik Stenson (SWE) 71-70-70, Justin Leonard 68-73-70, Bill Haas 68-71-72
212 - Brian Stuard 67-76-69, Steve Stricker 71-70-71, Zach Johnson 69-71-72, Brian Davis (ENG) 72-67-73
213 - Rory McIlroy (NIR) 70-74-69, Rory Sabbatini (RSA) 71-73-69, Adam Scott (AUS) 77-67-69, Hideki Matsuyama (JPN) 70-71-72