Cole Hammer is the leader after the first round of the RSM Classic, enjoying his only round for the week at Sea Island Resort's Plantation course on Thursday to post an eight-under 64.

The RSM Classic utilizes two courses at Sea Island Resort – the par-72 Plantation course, and the par-70 Seaside course. Each competitor will get one round on each course before the cut heading into the weekend, with the final two rounds to be played on the Seaside course.

Starting on the back-nine, 23-year-old Hammer posted nine birdies and seven pars from his first 16 holes, before his first blemish came with a bogey on the 17th to finish alone atop the leaderboard at eight under.

In second place is Ben Griffin, who also played the Plantation course, going bogey-free for his seven-under 65.

Beau Hossler and Callum Taren are tied for third after shooting six-under 64s on the Seaside course, with that appearing as the harder of the two tracks. 

There is a logjam tied for sixth at five under, and of the 16 payers to shoot five under or better, only four – Hossler, Taren, Chris Gotterup and Andrew Putnam – did it on the Seaside course.

Rising talent Sahith Theegala and recent winner of the Bermuda Championship Seamus Power are one further back at four under, with Italy's Francesco Molinari and Canada's Taylor Pendrith at three under.

It was a tough day out for some of the field's biggest names, with former Masters champion Danny Willett struggling to three over on the Seaside course, while former world number one Jason Day had similar issues on his way to four over.

The shot of the day went to Webb Simpson, who took advantage of his only round this week at the Plantation course with an ace on the par-three third hole. 

Ryan Palmer holds a two-stroke lead over the field after the second round of the Valero Texas Open.

Palmer, who shot four under in round one, finished with a six-under 66 to move to 10 under.

The American finished the round bogey-free, and three times carded back-to-back birdies on the second and third, eighth and ninth, and 14th and 15th.

Speaking to the media after his round, Palmer said the key to his success is to limit the severity of his mistakes.

"It's a golf course – if you get it off-line, you're going to struggle," he said. 

"I was able to keep the ball in front of me. When I've missed fairways, I've gotten fortunate breaks, I think. 

"[This] weekend, it's a matter of just avoiding those big misses."

Kevin Chappell worked his way into a three-way tie for second after he shot 65 for the best round of the day, and he is joined at eight under by South Africa's Dylan Frittelli and American Matt Kuchar.

Chappell – who is ranked as the world number 547 – played the course beautifully, nabbing an eagle on the par five second hole before going bogey-free and birdieing the eighth, ninth, 12th, 15th and 17th.

The leader after round one, Russell Knox, had a poor day, bogeying four of his first six holes on the way to shooting 76, dropping down to three under and a tie for 27th.

With the cut-line at even par, Jordan Spieth followed up his even par first round with a 70 on Friday to sneak into the frame.

Plenty of notable names who will hope to contest the US Masters crown next week failed to make the cut, including Jason Day, Rory McIlroy, Rickie Fowler and Bryson DeChambeau.

Russell Knox's bogey-free 65 earned him top spot on the Valero Texas Open leaderboard after the first round of action at TPC San Antonio.

The Scotsman was excellent all day, highlighted by his four consecutive birdies starting on the 12th hole to finish seven under.

He is one stroke ahead of Denmark's Rasmus Hojgaard, who eagled the par-five 18th to finish at six under and make up for his double-bogey on nine.

Speaking to the media after his round, Knox spoke about getting control of his driver, and the potential to play in next week's US Masters.

"I would love to win and get to play next week," he said. 

"I know my game is good, so I've got to keep playing well and see if I can have a great finish.

"I've been a little more consistent tee to green. I'm back to kind of feeling like the way I should be playing, which has been nice.

"Off the tee's been kind of important for me. Over the last couple years I just kind of got off track slightly, hitting a few wayward tee shots.

"I've worked hard with my coach, Mark McCann, and we've really gone back to fundamentals, got my set-up correct and it just gives me the freedom to kind of swing away.

"I know it's never going to be perfect, but the last couple months it's really been a strength of mine again."

Matt Kuchar and Englishman Aaron Rai are in a four-player tie for third at five under, with India's Anirban Lahiri and Australian Matthew Jones part of the large contingent at four under.

In-form Canadian Corey Conners finished tied with Richard Bland and Tony Finau with a big group at two under, with Ian Poulter and Keegan Bradley one shot further back.

It was an up-and-down round for Rickie Fowler, with his bogey on 18 forcing him to accept even-par for the day, which he shared with stars Rory McIlroy and Jordan Spieth.

Bryson DeChambeau and Lee Westwood highlighted the group at plus one, while Jason Day and Hideki Matsuyama will be fighting to make the cut after carding plus two.