Rory McIlroy failed to build on an encouraging start to his third round as he slipped out of contention at the Frys.com Open.
The world No 3 birdied looked set to mount a charge on 'Moving Day' at the Silverado Country Club in California, but three bogeys in a torrid four hole stretch on the back nine saw him plummet down the leaderboard.
He looked sharper with the putter early on as he holed from 12 feet for birdie at the first and converted a delightful approach to six feet at the third, but he came up short with his second to the next and could not get up and down for par.
McIlroy bounced back when he almost holed his 65-yard pitch at the eighth, but any hopes he had of putting pressure on the leaders took a huge hit when he bogeyed 11, 12 and 14 - missing two par putts from inside six feet.
To his credit, he got an 11-footer to drop for birdie at the next and clawed another shot back with a deft pitch-and-putt at the long 16th, and he did well to save par from eight feet at 17 after he was fortunate to avoid a nasty injury.
Emiliano Grillo, playing in the group behind, was inexplicably cleared to attempt to drive the green while McIlroy, Kyle Reifers and Adam Hadwin had yet to hole out, and Grillo's ball landed inches from McIlroy's foot and almost hit Reifers on the leg.
When asked afterwards how close the ball came to hitting him, McIlroy joked: "Missed me by a couple of inches. Would have put me out of my misery, to be honest with you."
Asked about the incident, Grillo said: "Everybody agreed that they were going up from the green to the guy standing on the tee. We thought they were waiting for us to hit. I was first, and I kind of heard something that I almost hit him, but I really apologise. Hopefully he's all right and he continues to play well as always. That would have been bad."
McIlroy split the fairway at the par-five last, but his second bounded through the green and, after chipping to just inside 10 feet, his tentative birdie putt broke right in front of the cup.
He struggled to hide his frustration as he tapped in for a 71 which left him eight shots off the lead and playing for pride on the final day.
"It was another one of those days that nothing really went for me, I just couldn't get anything going, got a little frustrated," McIlroy said afterwards. "I'm going to try and play a good round on Sunday, but I've got one eye on this and one eye further down the road.
"I'm looking at the three tournaments I've got coming up, which are important to me because I want to try to win the Race to Dubai again."