Chris Kirk, seeking his first PGA Tour title since 2015, and recent winner Webb Simpson shared the lead Friday after the second round of the Rocket Mortgage Classic in Detroit, Michigan.
Kirk, 35, walked away from golf last year, sidelining himself for seven months to address depression and alcohol abuse.
He grabbed a share of the halfway lead at Detroit Golf Club with a seven-under par 65 that included a birdie hole out from a bunker at the 11th and a chip-in for birdie at the 12th.
He had opened his round with three straight birdies and was 13 under for the tournament before a bogey at 18 capped his seven-under 65 for a 12-under total of 132.
Simpson, a former US Open champion who won the Heritage two weeks ago, had eight birdies in his eight-under 64.
The world number six Simpson stuck his approach within two feet of the pin for birdie at the ninth and holed out from a bunker for birdie at 16 on his way to the top of a jam-packed leaderboard.
World number 10 Bryson DeChambeau headlined a group of six players sharing third on 133 that also included Ireland's Seamus Power and Americans Matthew Wolff, Mark Hubbard, Ryan Armour and Richy Werenski.
It was a further stroke back to American Kevin Kisner and Austrian Sepp Straka -- whose brother, Sam, is on the bag for Kirk this week.
Although the most recent of his four US PGA Tour titles was at Colonial five years ago, Kirk said a new found perspective since his self-imposed hiatus -- and a recent win on the developmental Korn Ferry Tour -- have buoyed him.
"I'm very thankful to be out here playing again and I'm really enjoying competing," he said. "But at the same time I realize there are things that are a lot bigger than this ... I'm just happy to be in a really good place."
He said his Korn Ferry victory had showed him he could put together solid rounds, and his faith in that wasn't shaken by a tough finish that saw him have to sink a testing six-footer to save par at 17 before a bogey at the 18th -- where his four-footer for par lipped out.
"I didn't quite do as good a job of (maintaining momentum) late in the round today," he said. "But at the same time I felt I was in the right place mentally.
"I was trying to stay aggressive and trying to just keep making birdies. It didn't quite work out, but I'm proud of the way I played."
Simpson hit 13 of 14 fairways and 17 of 18 greens in regulation, and at the only green he missed -- at 16 -- he made birdie from a greenside bunker.
DeChambeau, who was frustrated after four bogeys in his first-round 66, minimized his mistakes in his second-round 67 that included five birdies without a bogey.
"Making those mistakes was getting on me," DeChambeau said. "Coming off with a clean card today makes me feel really good and finishing up with a birdie gives me some inspiration for tomorrow to play well."
Wolff, a second-year tour player seeking his second tour title, got to 11-under with an eight-under par 64, teeing off on 10 and stringing together six straight birdies from the 14th through the first to climb the leaderboard.
Armour also signed for a 64 that included a hole in one at the par-three fifth.
Ireland's Power, Hubbard and Werenski all signed for 66.
132 - Chris Kirk 67-65, Webb Simpson 68-64
133 - Seamus Power (IRL) 67-66, Matthew Wolff 69-64, Bryson DeChambeau 66-67, Mark Hubbard 67-66, Ryan Armour 69-64, Richy Werenski 67-66
134 - Kevin Kisner 65-69, Sepp Straka 68-66
135 - Brian Stuard 68-67, J.J. Spaun 66-69, Matt Wallace (ENG) 66-69, Hudson Swafford 67-68, Brandon Hagy 67-68, Doc Redman 65-70, Troy Merritt 68-67, Tyrrell Hatton (ENG) 68-67, Cameron Tringale 68-67