Stadler on Thursday had a one-stroke lead over Sweden's Henrik Stenson, Ryan Palmer and Colombian Camilo Villegas.
Australian Jason Day and American Matt Kuchar were a stroke further back at 66.
Stadler parred the final five holes.
"I hit the ball pretty well. It was a fun, enjoyable round," said Stadler. "I know I have to play well just to move on to next week. At the same time, it's out of my control.
"It's to the point where I was going to get what I was going to get. Anything past here is probably a bonus the way I was going."
World number one Tiger Woods, whose five victories this season sent him into the playoffs atop the points standings, also played without a bogey, posting a four-under 67 at Liberty National Golf Club.
He was tied in the clubhouse with Zimbabwe's Brendon de Jonge, Canadian Graham DeLaet and fellow Americans Nicholas Thompson, Matt Every and Morgan Hoffman, while Harris English was also at four-under having played just six holes.
Two weather delays lasted a total of five hours and 51 minutes. No one who teed off in the afternoon played more than nine holes and some completed only two.
Stadler knew he was in for a long wait before he'd have a chance to start round two and try to build on his lead.
But he was pleased to have completed the opening round.
"I don't know what time we are going to start tomorrow," he said. "It's going to be late. But I prefer to be on this side where we don't have a marathon day ... it won't take as big of a toll as the other guys."
Woods, showing no sign of the sore shoulder and neck he spoke of early in the week, hit 13 of 18 greens in regulation. He teed off on 10 and birdied three straight holes starting at the 14th, then picked up one more bogey at the par-three fourth.
He capped his round with a par-save from the greenside rough at the ninth.
"It was a long day, then tomorrow will be a short one, and Saturday will be pretty much a marathon," said Woods. "The course was slower and we got a couple mud balls out there. You could be aggressive, though."
Defending champion Nick Watney is one of 11 players at three-under, as he opened the first tournament of the 2013 FedExCup playoffs with a 68.