Watson also sitting on 12 under after Zurich Classic third round
Webb Simpson carded a five-under-par 67 to end the third round of the Zurich Classic of New Orleans in a tie for the lead with Bubba Watson.
The 25-year-old American reeled off five birdies in a row from the second hole to join his big-hitting compatriot at 12 under overall.
Simpson is still searching for his first PGA Tour title, with second place at the Transitions Championship in Tampa Bay in March his best result to date.
There, he shot 67s in each of his first three rounds before a 69 on the final day saw him just miss out on the title to Gary Woodland.
Simpson said: "The number one thing is I proved to myself (at the Transitions) that I can win. I was right there until the last hole. I'll carry that confidence from that tournament into tomorrow."
Watson finished with a third round of 70, recording four birdies - including one at the last despite finding the bunker - but also dropped two shots.
"The greens are getting pretty quick," Watson said. "It was tough making putts. I was just trying to cozy the ball up there."
Steve Stricker and KJ Choi are two behind the leaders in a group of six at 10 under which also includes George McNeill, whose 65 was the best round of the day.
England's Luke Donald finished the third round five shots back after carding a two-under par 70, leaving him at seven under for the tournament.
