Graeme McDowell's second round 74 saw him drop 30 places to 36th at the Texas Open on Friday night.
The Irishman was unable to follow up on his impressive first round 68; starting on the back nine he hit birdies on the 12th and 14th holes, but was derailed by back to back bogeys on the 15th and 16th , before another on the par 5 18th.
Things didn’t improve much on the front nine, with two more bogeys on the first and fifth, before steadying the ship with a birdie on the seventh.
McDowell is now two under par, six shots off the long-hitting Tony Finau who stumbled at the final hole to fall back into a share of the second-round lead with fellow American Bud Cauley (-8).
Finau, buoyed by an eagle at the par-four 11th, looked set to enjoy sole possession of the lead at the end of the day until he bogeyed the par-five 18th, though he still carded an excellent seven-under-par 65 at TPC San Antonio.
The one-time PGA Tour winner joined Cauley (66) at eight-under 136, with Australian Cameron Smith in a group of three players one shot behind.
Cauley was upbeat after hitting the front in his quest for a breakthrough victory on the PGA Tour, after previously finishing third on three occasions.
“I hit it a little better yesterday and didn’t quite convert on some of the putts. Today I putted really well,” he said.
“It was windy out there. I knew I was going to miss some greens and I was able to hit some good chips.”
Smith, one shot back, also enjoyed his fair share of good breaks in his 65.
“It all fell into place,” he said. “Everything I hit, whether it was a rubbish shot or a good shot, went close to the hole. My short game was really good. I think I had three chip-ins.”
Last year's PGA Championship winner Jimmy Walker, who was recently diagnosed with Lyme disease, also moved into contention at his hometown event, three strokes behind.
Walker said on Friday he planned to take a break from golf to undergo treatment for the tick-transmitted bacterial infection that can cause headaches, fever, fatigue, rashes and, if less untreated, can spread to the heart, joints and nervous system.
He said he started feeling fatigued late last year, but was not diagnosed accurately until two weeks ago, just before the Masters.
“It’s nice to know it’s something and we can do something about it,” he told the PGA Tour official website.
“It’s something you don’t really like to tell people how tired you are, how fatigued you are ... are you just going crazy, getting old?”
Ireland’s Séamus Power hit an eagle on the par 4 fifth, on his way to a 72. He is level par overall, and one shot inside the cut for the weekend.
Meanwhile, Ian Poulter accepts the hard work must begin now after he lost his PGA Tour card by missing the cut.
The Ryder Cup favourite, a two-time winner on tour, needed to bank at least $30,624 (€28,550) by finishing in the top 30 in San Antonio but he was unable to make it to the weekend.
Poulter has been playing on a medical exemption following a foot operation last year but, with that expiring, he needed to earn his card.
The 41-year-old, who has a highest finish of 11th this season, may still be seen at PGA events but will now require invitations if he is to appear on the PGA circuit. He is still eligible to play on the European Tour and can go through qualifying for the forthcoming US Open and Open.
“This is not to say the clubs are going to go away and you are never going to see me again,” Poulter told Sky Sports 4.
“It means I have got some work to do, I am playing next week in New Orleans and who knows, golf is a funny game I could easily win and then things are a little different.
“But I don’t know if I will be in tournaments or out of tournaments so what it will mean is, and what is the most frustrating thing for the next few months, I can’t plan a schedule. I have to be ready to go on any given Monday to go to an event.
“I will try and qualify for the US Open, I will try and qualify for the Open, I will play some events in Europe, I will try and play some events over here, so I will do what I have to do.”
A first round of three over left him facing an uphill challenge and Friday’s one-under 71 was not enough to keep him in the mix.
He managed four birdies in the front nine but also made three bogeys to stifle his momentum.
Tweeting after his round, Poulter wrote: “The best thing about golf is it gives you what you deserve, Also when the chips are down you find out who your real friends really are !!!!!”
Responding to one message of support from a fan, he added: “I guess the road needs re tarmacking after a good few miles. A career isn’t a career without the odd bump along they way.”
