Daniel Berger shot a second successive five-under-par round of 65 to claim a three-stoke lead at the halfway mark of The Honda Classic.
The Floridian continued to star in his home state, notching six birdies and just the one bogey - his dropped shot at the par-three 15th Berger's first blemish of the week after a bogey-free opening round at Palm Beach.
England's Danny Willett dropped back down the field, though, and is now tied for 22nd on one under par.
The 2016 Masters champion suffered three bogeys in a two-over par 72 having begun the tournament with a three-under 67 on Thursday.
Willett is joined on one under by fellow Englishmen Lee Westwood, who shot an even-par 70, and Aaron Rai, who stumbled to a two-over 72 at the PGA National Resort.
- Honda Classic: Latest scores | When is the PGA Tour on Sky?
- Bryson DeChambeau to return at Arnold Palmer Invitational
It was a better day for Shane Lowry, who carded four birdies and a solitary bogey in a three-under-par 67 to move into a share of eighth place - although the Irishman is seven strokes behind leader Berger.
Scotland's Russell Knox is one shot back from Lowry on two under par, leaving him in a tie for 12th place.
World No 21 Berger said: "Every tournament I play I want to win but it would be especially nice to win here having so many friends and family with me.
"But you just can't focus on that, you've got to take it a shot at a time and really just stay patient."
Americans dominate the leaderboard at Palm Beach with Kurt Kitayama - who led after round one by dint of a six-under 64 - and Chris Kirk in second place at seven under par and Mark Hubbard in third at six under, alongside Canada's Adam Svensson.
Hubbard's six under for the day was the joint-best round, matched by Austria's Sepp Straka, who now lies in a tie for sixth with America's Chase Seiffert at five under.
Kitayama had a real mixed bag of a round, beginning with a birdie, ending with an eagle and picking up three bogeys and another birdie in between as he shot one-under for the day.
Watch the Honda Classic throughout the week live on Sky Sports. Live coverage continues from 11.45am on Saturday on Sky Sports Golf.