ORLANDO, Fla. — Vijay Singh was forced to take four days off from practicing, which was unprecedented. He found himself atop the leaderboard one week later at the Arnold Palmer Invitational, which is not surprising in the least.

Weakened by a stomach virus that caused him to lose 18 pounds in five days, Singh recovered in time to make a strong defense of his Bay Hill title by chipping in twice Friday on his way to a 5-under 65 and a two-shot lead over Carl Pettersson.

The 45-year-old Fijian looked like the model of athleticism on a day of gray clouds and occasional rain, not even remotely resembling someone afraid to stray too far from the bathroom for four days.

"I've got a very heavy shirt on. I can see my ribs," said Singh, who was at 9-under 131. "I thought I was going to pull out of this tournament, but on Friday, I just started to hit a few (balls). And that was it."

What he couldn't see on the leaderboard was Tiger Woods, who hasn't been this far out of the lead since the British Open.

The world's No. 1 player also looked sick, but only after watching putts come up short on shoddy greens. Woods, trying to continue a winning streak that stretches all the way back to September, had to settle for nine straight pars to close out a 2-under 68. He was seven shots behind going into the weekend.

"I'll have to play better and make a lot more putts that I have been," Woods said. "I just wasn't swing the club very well today. And when I did put myself in position to make a putt, I didn't make them."

After hitting a tee shot on the 16th that stopped next to a grandstand on the 17th, Woods still had a 15-foot birdie putt that rolled and wiggled and bumped and eventually slid by the hole. By this point, he only smiled.

"Runs like a fairway," he said under a breath.

But they are the same for everybody, and scoring has been reasonable.

Pettersson opened with three straight birdies on his way to a 65. Former U.S. Open champion Jim Furyk, coming off an unproductive West Coast Swing, birdied the last hole for 67, leaving him in the group at 134 that included Lee Westwood (68) and Ken Duke (67).