The Irish players are all in danger of missing the weekend at the US PGA Championship.
Kevin Kisner has a two-shot lead over the field at six-under through 13 holes.
Rory McIlroy, a twice previous winner at Quail Hollow, is three-over for his 15 holes today and now four-over for the tournament.
Starting from the 10th, McIlroy carved his second shot on the 591-yard par five over the crowd to the right of the fairway and saw it bound down a cart path which runs along the side of the next hole.
The world number four was left with a seemingly impossible third shot from around 60 yards, but produced a brilliant low pitch which bounced off the path, through a bunker and ran across the green before stopping on the fringe.
From there McIlroy chipped to two feet and holed for par, giving a wry smile and raising his eyebrows to members of the media as he made his way to the 11th tee.
The 28-year-old also parred the next four holes in more orthodox fashion, but missed from eight feet for birdie on the short par-four 14th, the hole he double-bogeyed on Thursday.
A towering drive on the par-five 15th was followed by an approach into a greenside bunker, from where McIlroy splashed out and saw his ball hit that of playing partner Jon Rahm, who had needed two attempts to escape from the same hazard.
That left McIlroy further away from the hole than he should have been, but the Northern Irishman holed from seven feet for birdie to get back to level par for the tournament.
McIlroy safely negotiated the so-called Green Mile - the 16th, 17th and 18th - to remain level par at the turn.
Having dropped a shot on the second, McIlroy looked like pulling off another escapology act on the next after following a wayward drive by firing his approach over the trees and onto the green.
However, he then three-putted from 40 feet and when he also bogeyed the fifth to fall back to three over par, he was suddenly just one shot inside the projected cut.
Another bogey on the sixth left McIlroy in a similar position to which Spieth found himself on day one, the American standing three over with three to play and needing to take advantage of the relatively easy remaining holes.
And that was precisely what McIlroy did, getting up and down from just off the green on the par-five seventh and, after another massive drive on the 350-yard eighth, pitching to four feet to set up another birdie.
Graeme McDowell is eight-over through 12 and five shots outiside the projected cut mark.
Shane Lowry is back out from three-over soon with Padraig Harrington teeing off his second round from eight-over.
Kisner, who had shared the overnight lead with Denmark's Thorbjorn Olesen, had also started on the back nine and carded three birdies and a bogey to improve to six under par.
Olesen was among the afternoon starters alongside Open champion Jordan Spieth, who needs to win this week to become the youngest player to complete a career grand slam.
But another Jordan, England's Jordan Smith, was already on the course and climbing the leaderboard, birdies on the 10th and 13th taking the 24-year-old to three under par on his major championship debut.
The best round of the day was coming from 2013 champion Jason Dufner, who had covered the back nine in 32 to reach one under par, 12 shots ahead of playing partner Phil Mickelson, who had not recorded a single birdie in the first 27 holes.