Former FedEx Cup champion Bill Haas and 2009 British Open winner Stewart Cink moved into the joint lead at the Houston Open on Saturday but 18 others are within four shots of the Americans after three rounds.
Haas carded a five-under 67 and Cink entered the clubhouse after a 68, leaving the two at 11-under par for the tournament, one clear of countrymen Ben Crane (67), D.A. Points (71), Jason Kokrak (71) and overnight leader Steve Wheatcroft (72).
Nine other players are within two of the lead including major champions Louis Oosthuizen of South Africa (65), Argentine Angel Cabrera (69) and American Keegan Bradley (67) plus former world number one Englishman Lee Westwood (67).
Americans Bud Cauley (65), Billy Horschel (67), Kevin Chappell (67) and Cameron Tringale (69) plus Swede Henrik Stenson (68) also are at nine-under.
A 67 moved Phil Mickelson to six-under for the week, just five shots off the pace.
Cink is searching for a seventh PGA Tour title and his first since claiming the Open Championship.
The 39-year-old's form over the past few seasons has been lacking with just two top 10s since 2011 but after a round including five birdies and just one bogey, he claimed he was not surprised by his lofty position on the leaderboard.
"I have been striking the ball real well and this course is a good ball strikers' course because there is almost always one side of the course that is unplayable and you have to eliminate that side," Cink told reporters.
"If you are in control off the tee and in control with your approaches you're going to be able to eliminate that most of the way.
"I could see something like this coming, I'm just excited to have a chance at a win and to be teeing off late on Sunday."
Cink is well aware of the tightly packed leaderboard.
"It's almost like we're starting again in a sprint so you can't force anything," he said. "You have to allow it to happen and come out with an accepting attitude."
Haas is hoping to add the Houston title to his family trophy case for the second time after father Jay won the event back in 1987.
It would be his fifth tour title and first since the 2012 Northern Trust Open.
"It would be great to win. I don't remember Dad winning (Haas was five) but it was great to win at the Bob Hope (2010) to share that title and certainly winning here at the Houston Open would be just as special," Haas said.
"Anytime to win out here you have to play well and you have to make a lot of putts.
"There is going to be four or five tee shots and some putts you don't feel good over but hopefully you can handle them under the gun."
Former world number one Rory McIlroy had appeared to find some form after four birdies in his opening 12 holes, but closed with three bogeys to shoot 71 and sit at two-under, nine back in a tie for 48th.
Wheatcroft, a Monday qualifier without status on tour, made an important up and down for bogey on the 18th to be just one back after he nervously shanked a greenside bunker shot.