IRVING, Texas — Louis Oosthuizen is still looking for a remedy for his recurring back issues.
A victory at the Byron Nelson Championship would sure make him feel much better.
“The last year and a half was really frustrating,” he said.
Oosthuizen birdied four of the last five holes for 6-under-par 64 on Saturday and a share of the third-round lead with former Georgia golfer Brendon Todd.
Mike Weir (67), James Hahn (65)and Gary Woodland (66) are a stroke behind the co-leaders.
Scott Scheffler, a 17-year-old from Dallas who won April’s Junior Invitational at Sage Valley Golf Club, made a hole-in-one on the 218-yard second hole.
He is the fourth amateur since 1983 with an ace in a PGA Tour event. He shot 69 and is tied for 38th place, eight shots behind the co-leaders.
Oosthuizen, the 2010 British Open champion had the low round of the day after recovering from bogeys on two of the first four holes.
“I made a nice birdie on 5, and just really made some good putts,” Oosthuizen said. “Every opportunity I had for birdie I actually made. My eye was good today, and I hit a lot of them really close.”
Todd made 12 consecutive pars before holing a 4-foot birdie at No. 18 for 68 to match Oosthuizen at 10-under 200.
On the morning of the Nelson’s final round last year, Oosthuizen withdrew because of a neck issue. He missed extended time last season, and is still bothered by the back even though he won at home in South Africa in January.
Weir, the 2003 Masters Tournament champion, hasn’t had a top-25 finish since 2010 when the Canadian had an elbow injury.
“That’s what I’ve been working toward the last few years, to get myself back here in this position, and looking forward to the challenge,” said Weir, the 44-year-old left-hander.
Morgan Hoffmann twice fell out of the lead after hitting drives left into the water and making double bogey, at Nos. 11 and 18.
He finished with 68 and is tied for sixth at 8-under with three-time major champion Padraig Harrington, Marc Leishman and Graham DeLaet.
Todd’s only bogey was at the 420-yard fourth hole, when his approach went over the green and he two-putted from 8½ feet.
But that was sandwiched by long birdies.
After beginning the day with a two-stroke lead, Todd had to make a 4-foot birdie on No. 18 to regain a share of the lead.
“I wanted to get one more birdie under my belt so I could be that much closer to shooting the score I need to win Sunday,” Todd said.
Oosthuizen was 2 under and well off the pace after his bogey at No. 4, when he hit his second and third shots from the rough and then was in a greenside bunker. The South African blasted to about 10 feet and had to make that putt for bogey, then made three birdies in a row.
He made an 8-foot birdie putt at the par-3 fifth, and followed that with an approach to 6 feet at No. 6 and a two-putt from 58 feet at the par-5 seventh. There was another string of three consecutive birdies at Nos. 14-16 before a closing 4½-footer at No. 18.
“It’s always nice finishing a round on a high,” Oosthuizen said. “You sort of feed off that the next day, and that keeps you going.”
Hoffmann was at 10 under and alone in the lead when he hit his drive into the water to the left at the 320-yard 11th hole, with Weir was just ahead on the green.
Weir sank a 2-footer for his fourth consecutive birdie to get to 10 under. Hoffmann then hit another drive after his penalty and wound up with a double bogey. But Weir missed putts from about 5 feet on both Nos. 15 and 16, the latter lipping the cup.
Hoffmann was again 10 under after birdies at Nos. 15-16, but hit his drive at No. 18 into the water and then hit twice out of the same greenside bunker.
Dallas native Jordan Spieth, now 20 and ranked eighth in the world, made the Nelson cut as an amateur at ages 16 and 17. Spieth shot 73 on Saturday and was even par overall.