Shane Lowry is five shots off the lead after carding a 69 in his opening round at the Valspar Championship in Florida.
The Offaly native, fresh from last week's weather-affected Players Championship at Sawgrass where he was briefly in contention, finished on two under, with Graeme McDowell four shots further back on four over.
The duo teed off together just after 5pm Irish time, Lowry making a fast start with a birdie on the par-five first.
He then picked up a further shot on the fourth before a bogey on eight dropped him back.
But Lowry rebounded on the back nine to climb up to three under with birdies on 11 and 14 which temporarily moved him within four shots of the lead.
But a bogey on the final hole saw the 34-year-old slip back to two under and five off the lead held by Jhonattan Vegas, Sam Burns, Adam Hadwin and David Lipsky after the quartet carded 64s.
They led by one stroke from Australia's Danny Lee and three more Americans in Scott Stallings, Richy Werenski and Davis Riley.
Justin Thomas, who holed a 63-foot putt for eagle on the 14th, was one of three players on five under along with Kramer Kickok and Doc Redman.
Burns carded nine birdies in his round including two back-to-back on the last two holes after a bogey, one of two during the day, on the 16th.
Burns felt comfortable back at the scene of his success last year but tried to put that out of his mind.
He said: "I think I'll look back forever on that event, it being my first win. Wins don’t happen out here often, so I think it’s good to reflect and just be extremely grateful and thankful that they happen and that’s what I’ll try to do.
"But the thing about last year is it has nothing to do with this year. So many things are different. There’s not much correlation between the two.
"So I think just trying to treat this week as its own, go out there and prepare well, prepare to play good golf."
Lipsky recorded seven birdies on a blemish-free card while Vegas’s round, which began on the back nine, included an eagle at the par-five first.
Hadwin chipped in from off the green on the sixth for one of his eight birdies during the day.
"A lot of things went right to shoot 64 around this place, just a lot of good consistent golf," said Hadwin, winner of this event in 2017.
"I wouldn’t say that I felt great off the tee, but I was never in any trouble. I hit it really well."
McDowell will be aiming to bounce back in Friday's second round after four bogeys and two birdies across his 18 holes.
Two of those dropped shots were back-to-back on eight and nine before an eventful stretch of four holes on 11 to 14 with birdies sandwiching a pair of bogeys as he finished with a two-over 73.