Adam Schenk stood alone atop the leaderboard at seven under through two rounds at the Valspar Championship, with major champions Jordan Spieth and Justin Thomas both in the hunt.

Schenk, a 31-year-old American who has never won on the PGA Tour, was tied for the first-round lead after starting his week with a five-under 66. He followed it up with a 69 on Friday, collecting four birdies to go with two bogeys to earn the outright lead heading into the weekend.

Kramer Hickok was the only player one back at six under, shooting a pair of 68s, while some big names were breathing down his neck at the Innisbrook resort in Florida.

Three-time major champion Jordan Spieth (70) sat tied for third at five under, joined by fellow top-30 ranked talent Tommy Fleetwood (69), as well as Cody Gribble (65) and Davis Riley (68).

Spieth spoke positively of his round but found the windy conditions challenging.

He said: "I drove the ball maybe the best of the year today. Gave myself a lot of chances with some wedges. There's a lot of back pins and I just got a little tentative for a few holes.

"Then I decided to attack one on 10 and flew the green. I couldn't quite get my distance control down on some scoring clubs. But when the wind here is gusty like that and the green depths are so small, it gets really, really tricky and doesn't take much. Keep driving the ball like that, I feel like I can fine-tune some of the scoring clubs and maybe get a few more looks."

England's Matt Wallace (67) and Germany's Stephan Jaeger (72) featured in the five-man group rounding out the top 10 at four under, while two-time major champion Justin Thomas headlined the logjam at three under, still well in the mix after a 70.

After a horror quintuple-bogey nine during his first round, reigning U.S. Open champion Matt Fitzpatrick was unable to recover and make the cut, missing out by two strokes at three over after a level-par 71.