Luck gained a late start in the event courtesy of the withdrawal of Kevin Na who is suffering a neck injury.
The demanding Copperhead layout again took its toll, but despite a poor start and finish to his round Luck did enough in between to improve 23 places and be well placed heading into the weekend.
Luck’s form in his rookie season has been below expectations but the PGA Tour takes time and patience on which to find a comfort zone and on one of the more difficult layouts on the PGA Tour Luck’s significant skills have assisted him to the edge of contention.
A bogey at his final hole when unable to get up and down from a green-side bunker was perhaps a little disappointing for Luck but he will be delighted to have bounced back from two missed cuts in his last three events to be so close.
Matt Jones is the next best of the Australians in the event, a round of 68 improving him 57 positions to 23rd place, he and Luck the only two Australians to make it to the weekend.
Jason Day, Rod Pampling, John Senden and Cameron Davis missed the cut.
Joint leader, Casey, has been playing beautifully for much of 2019 but a missed cut at last week’s Players Championship appeared to have slowed a run which has included two runner-up finishes and one 3rd place.
Casey though is the defending champion and loves the golf course and said as much after his round of the day 66.
“It's a great golf course, said the Englishman. “I think it's one of the best we play on TOUR. Might be the best one we play on the Florida swing. You know I like it because I'm defending champion. Champions always like the golf courses they win on. But it's really, quality.
“It's very tough as well. The difference between hitting the green and landing just short, the dispersion of where the shots finish is high. There's a premium on ball striking.
“I feel really good about it because last week was rubbish. I, for whatever reason, I struggle a little bit around Sawgrass and that frustrated me, annoyed me, coming in here trying to defend my title, which I would love to do because I never defended a professional title.
Cook, a father for the first time this year, is playing just his 6th event of the year but it has been a difficult start to 2019 for obvious reasons.
“Yeah, you know, good play's going to come, it's just being patient, that's been the big thing the last few weeks. Two MDF's already and I think three missed cuts here in the spring, so it's been tough, especially with last year I think I made 21 out of my 25 or 26 cuts.
“So just being patient is the big thing at first right now and when we get in a groove we'll be all right.”
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