Jeff Maggert shot his second 66 to take the lead at 12 under par after two rounds at the rain-delayed Houston Open.
The 48-year-old Maggert, trying to win his hometown event for the first time in 24 starts, had eight holes left in his second round when play resumed early Saturday.
A total of 70 players were still on the course when play was suspended by darkness on Friday. The tournament's schedule was set back by a thunderstorm that dumped 1¼ inches of rain on Thursday.
Defending champion Phil Mickelson (70), J.B. Holmes (67), Tommy Gainey (67), and Greg Owen (69) completed their second rounds on Friday and were at 9 under. First-round leaders Angel Cabrera and Carl Pettersson were also in the group at 9 under after finishing rounds of 70 on Saturday.
Three-time major champion Ernie Els, who must win to qualify for next week's Masters, was in the group at 5 under after a second-round 69.
A total of 90 players made the 36-hole cut at 2 under or better. Another cut was coming after the third round.
Maggert missed five straight cuts coming into this week.
Playing in calm, cloudy conditions early Saturday, Maggert hit his approach to No. 3, his second hole of the day, to within a foot and sank the putt to join overnight leaders Brian Davis and Louis Oosthuizen at 11 under par. Maggert then birdied both par 5s on the front nine to take the outright lead at 13 under.
"It's a strange game," he said. "I just had a little stretch there where I wasn't hitting it that great. Just struggled a little bit, but this week, I've certainly turned it around."
Maggert three-putted on the par-3 9th for his first bogey of the tournament. He was remarkably consistent in his first two rounds, hitting 12 of 14 fairways and 16 of 18 greens and needing 28 putts in each one.
"That's usually the formula for some pretty good scoring," Maggert said. "I've been hitting the ball really well this week, a lot of shots close to the hole, where I'm not having to make 15- or 20-footers for birdies."
Driscoll made birdies on two of his last three holes on Saturday morning, including a 22-footer on the par-5 8th hole. The 34-year-old Driscoll has two runner-up finishes on the tour, including the 2009 Texas Open in San Antonio.
Mickelson finished a 65 on Friday morning, then started his second round on No. 10 about an hour later. His afternoon round stalled after he birdied 13 and 15, the two par 5s on the back nine. He hit his tee shot over the green on the par-3 16th and bogeyed, then parred the next five holes.
"I played pretty well the second round, but I didn't get the score that I had hoped," Mickelson said. "I've got to light it up this weekend."
Mickelson played with Fred Couples, who won on the Champions Tour last week. Couples, who played at the University of Houston and has made 19 consecutive cuts at the event, was 4 under through two rounds.
Couples moved within two shots of the lead, but dropped back when he dunked his tee shot in the water on the 488-yard, par-4 18th hole and took a double bogey. The 52-year-old Couples shot a 73 on Friday afternoon.
The Houston Open became the run-up event to the Masters in 2007. Despite the delay, tournament director Steve Timms is hoping to finish the tournament by 5 p.m. Sunday to accommodate television as well as players heading to the Masters.
The 52-year-old Couples says the event is an ideal tuneup for the Masters, which he won in 1992.
"I think it's kind of an exciting time before Augusta," Couples said. "I can try and get the juices up."