Right behind him is just about everybody.
McGirt was at 12-under 201, two shots clear of George McNeill and Charlie Beljan.
McNeill, whose two wins were in the old Fall Series and an opposite-field event, started with an eagle and picked up a final birdie on the par-3 16th for a 66. Beljan, who lost in a playoff at Riviera last year to John Merrick, belted a 3-wood into 8 feet for eagle on the 11th hole and shot a 68.
The leaderboard was about as crowded as the 405, which was reduced to two lanes right off Sunset Boulevard. Twelve players were within five shots of the lead, which can be easy to make up at Riviera, especially with a leader new to this position.
"It's just 18 more holes, and whatever is going to happen is going to happen," McGirt said. "All I can do is go out and play the best I can."
Jason Allred, the feel-good story this week after Monday qualifying for his first PGA Tour event in more than three years, had a 67 and joined Brian Harman (68) at 204.
In Naples, Fla., Kirk Triplett shot a 5-under 67 in windy conditions for a share of the second-round lead with defending champion Bernard Langer in the ACE Group Classic.
Triplett matched Langer at 10-under 134 on TwinEagles' Talon Course.
Langer, also the 2011 winner and 2012 runner-up, followed his opening 64 with a 70. He won the season-opening event in Hawaii last month.
Northern Trust Open
William McGirt -12
George McNeill -10
Charlie Beljan -10
Jason Allred -9
Brian Harman -9