Las Vegas - Scotland's Russell Knox and American Andrew Putnam, both seeking a first PGA Tour title, shared the halfway lead Friday at the Shriners Hospitals Open in Las Vegas.
Putnam, making the fourth PGA Tour start of his career, had seven birdies and one bogey in his six-under 65, while Knox had six birdies and two bogeys in his 67.
They shared the lead in the second event of the US tour's 2014-15 season on 10-under 132 - one shot in front of Americans Andrew Svoboda and Tony Finau.
Finau climbed up the leaderboard with a 65, while Svoboda posted a 67.
Putnam, who earned his PGA Tour card for this season via the Web.com developmental tour, has made the cut on the elite circuit for the first time.
Knox, meanwhile, heads into the weekend trying to improve on his career-best finish on the tour - his playoff loss at the Honda Classic last March.
"I was all over the map," said Knox, who opened with a birdie at the first, then bogeyed the second and third. "I didn't feel real good with my swing, and I knew if I just made some pars, eventually something would click.
"And I made a couple of putts, which really settled me down," added Knox, who capped his round with a birdie at 18 for his share of the lead.
Spencer Levin and George McNeill shared the low round of the day with blistering eight-under-par 63s.
They were among a group sharing fifth place on eight-under 134 along with Webb Simpson (65), Ben Martin (66), Bo Van Pelt (68), Scott Piercy (67), Wes Roach (67) and Scotland's Martin Laird (70).
Laird had shared the first-round lead with former British Open champion Stewart Cink, who stumbled to a four-over 75 at TPC Summerlin to fall into a tie for 45th.Leading second-round scores on Friday in the US PGA Tour Shriners Hospitals Open (USA unless noted, par-71):
132 - Andrew Putnam 67-65, Russell Knox (SCO) 65-67
133 - Andrew Svoboda 66-67, Tony Finau 68-65
- Spencer Levin 71-63, Webb Simpson 69-65, George McNeill 71-63, Ben
Martin 68-66, Bo Van Pelt 66-68, Scott Piercy 67-67, Martin Laird (SCO)
64-70, Wes Roach 67-67
135 - Kevin Kisner 70-65, Brandt Snedeker 67-68, Tim Clark (RSA) 68-67
- Bill Lunde 68-68, Jason Bohn 68-68, Nick Taylor (CAN) 71-65, Hudson
Swafford 69-67, Cameron Percy (AUS) 68-68, David Hearn (CAN) 70-66
- Brooks Koepka 69-68, Scott Brown 70-67, Nick Watney 68-69, Alex Cejka
(GER) 69-68, Kevin Stadler 67-70, Hideki Matsuyama (JPN) 66-71, Ken
Duke 69-68, Jarrod Lyle (AUS) 66-71