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 a 6-under 64 on Saturday and a share of the third-round lead with Brendon Todd. Oosthuizen, the 2010 British Open champion, had the low round of the day after recovering from bogeys on two of the first four holes.

"Every opportunity I had for birdie I actually made," Oosthuizen said. My eye was good today, and I hit a lot of them really close."

Todd who made 12 consecutive pars before holing a 4-foot birdie at No. 18 for a 68 to match Oosthuizen at 10-under 200 in in Irving, Texas.

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.

Mike Weir, Cal's James Hahn (65) and Gary Woodland were a stroke back. Hahn, looking for his first PGA win, made five birdies in a row on the back nine on holes 12 through 16, and Woodland shot 66 with a double bogey at No. 7.

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 a 68 and was tied for sixth at 8 under with three-time major champion Padraig Harrington, Marc Leishman and Graham DeLaet. Dallas native Jordan Spieth, now 20 and ranked eighth in the world, shot 73 and is even par overall.

LPGA: Lizette Salas moved into position for her first LPGA Tour victory, playing 25 holes in 6-under par to take a three-stroke lead in the Kingsmill Championship in Williamsburg, Virginia. The 24-year-old former USC player shot a 3-under 68 in the completion of the rain-delayed second round and birdied three of the last five holes in the afternoon for a season-best 65. She had a 13-under 200 total on Kingsmill Resort's River Course. Second-ranked Stacy Lewis (70) and No. 3 Lydia Ko (67), both trying to take the top spot in the world from Inbee Park, were five strokes back.

Champions: Kenny Perry shot a 3-under 69 at Shoal Creek in Birmingham, Alabama, to reach 7-under 209 for a one-shot lead over John Inman after the third round of the Regions Tradition.